An Advanced Tape-Stripping Approach for High-Efficiency Sampling on Non-Absorbent Surfaces

Surface sampling is a frequent task in laboratory work and field studies. Simple methods usually have low efficiency in collecting target substances from surfaces. This study developed an advanced tape-stripping approach for efficient sampling on non-absorbent surfaces. A film-forming solution, prepared using polyvinyl alcohol, is applied to the target surface, where it covers and engulfs the surface deposits and then solidifies into an elastic membrane as it is exposed to air. The deposits are collected by stripping off the membrane and re-dissolving it in water. This new approach exhibited an efficiency of 100% in collecting uniform-size microspheres from glass surfaces and extremely high efficiencies (>96.6%) in detecting selected target DNA materials from glass and stainless steel surfaces. In comparison, the common swab-rinse method exhibited an efficiency of 72.6% under similar measuring conditions. The viability of S. aureus during sampling using the new approach decreased as the ethanol concentration in the applied solution increased. Using a solution with a mass ratio of ethanol of 17.6% balanced the effects of multiplication and degradation of the S. aureus on glass surfaces during sampling. Overall, the proposed approach exhibits high efficiency in collecting living and abiotic matter from non-absorbent surfaces, complementing existing sampling methods.

High attack rate in a Tong Lau house outbreak of COVID-19 with subdivided units in Hong Kong

Poor housing conditions are known to be associated with infectious diseases such as high Coronavirus disease 2019 (COVID-19) incidences. Transmission causes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in poor housing conditions can be complex. An understanding of the exact mechanism of transmission can help to pinpoint contributing environmental issues. Here, we investigated a Hong Kong COVID-19 outbreak in early 2021 in four traditional Tong Lau houses with subdivided units. There are more than 80 subdivided units of less than 20 m² floor area each on average. With a total of 34 confirmed COVID-19 cases, the outbreak had an attack rate of 25.4%, being one of the highest attack rates observed in Hong Kong, and ranked among the highest attack rates in reported outbreaks internationally. Tracer gas leakage and decay measurements were performed in the drainage system and in the subdivided units to determine the transport of infectious aerosols by the owner-modified sophisticated wastewater drainage pipe networks and the poor ventilation conditions in some subdivided units. The results show that the outbreak was probably due to multiple transmission routes, i.e. by the drainage pipe spread of stack aerosols, which is enhanced by poor ventilation in the subdivided units.

Aerosol transmission of SARS-CoV-2 due to the chimney effect in two high-rise housing drainage stacks

Stack aerosols are generated within vertical building drainage stacks during the discharge of wastewater containing feces and exhaled mucus from toilets and washbasins. Fifteen stack aerosol-related outbreaks of coronavirus disease 2019 (COVID-19) in high-rise buildings have been observed in Hong Kong and Guangzhou. Currently, we investigated two such outbreaks of COVID-19 in Hong Kong, identified the probable role of chimney effect-induced airflow in a building drainage system in the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We injected tracer gas (SF6) into the drainage stacks via the water closet of the index case and monitored tracer gas concentrations in the bathrooms and along the facades of infected and non-infected flats and in roof vents. The air temperature, humidity, and pressure in vertical stacks were also monitored. The measured tracer gas distribution agreed with the observed distribution of the infected cases. Phylogenetic analysis of the SARS-CoV-2 genome sequences demonstrated clonal spread from a point source in cases along the same vertical column. The stack air pressure and temperature distributions suggested that stack aerosols can spread to indoors through pipe leaks which provide direct evidence for the long-range aerosol transmission of SARS-CoV-2 through drainage pipes via the chimney effect.

Close contact behavior in indoor environment and transmission of respiratory infection

Close contact was first identified as the primary route of transmission for most respiratory infections in the early 20th century. In this review, we synthesize the existing understanding of the mechanisms of close contact transmission. We focus on two issues: the mechanism of transmission in close contact, namely the transmission of the expired particles between two people, and the physical parameters of close contact that affect the exposure of particles from one individual to another, or how the nature of close contact plays a role in transmission. We propose the existence of three sub-routes of transmission: short-range airborne, large droplets, and immediate body-surface contact. We also distinguish a "body contact," which is defined with an interpersonal distance of zero, from a close contact. We demonstrate herein that the short-range airborne sub-route may be most common. The timescales over which data should be collected to assess the transmission risk during close contact events are much shorter than those required for the distant airborne or fomite routes. The current paucity of high-resolution data over short distances and timescales makes it very difficult to assess the risk of infection in these circumstances.

Most self-touches are with the nondominant hand

Self-touch may promote the transfer of microorganisms between body parts or surfaces to mucosa. In overt videography of a post-graduate office, students spent 9% of their time touching their own hair, face, neck, and shoulders (HFNS). These data were collected from 274,000 s of surveillance video in a Chinese graduate student office. The non-dominant hand contributed to 66.1% of HFNS-touches. Most importantly, mucous membranes were touched, on average, 34.3 (SE = 2.4) times per hour, which the non-dominant hand contributed to 240% more than the dominant hand. Gender had no significant effect on touch frequency, but a significant effect on duration per touch. The duration per touch on the HFNS was fitted with a log–log linear distribution. Touch behaviour analysis included surface combinations and a probability matrix for sequential touches of 20 sub-surfaces. These findings may partly explain the observed variation in the literature regarding the microbiome community distribution on human skin, supporting the importance of indirect contact transmission route in some respiratory disease transmission and providing data for risk analysis of infection spread and control.

Infection Spread and High-Resolution Detection of Close Contact Behaviors

Knowledge of human behaviors is important for improving indoor-environment design, building-energy efficiency, and productivity, and for studies of infection spread. However, such data are lacking. In this study, we designed a device for detecting and recording, second by second, the 3D indoor positioning and head and body motions of each graduate student in an office. From more than 400 person hours of data. Students spent 92.2%, 4.1%, 2.9%, and 0.8% of their time in their own office cubicles, other office cubicles, aisles, and areas near public facilities, respectively. They spent 9.7% of time in close contact, and each student averagely had 4.0 close contacts/h. Students spent long time on close contact in the office which may lead to high infection risk. The average interpersonal distance during close contact was 0.81 m. When sitting, students preferred small relative face orientation angle. Pairs of standing students preferred a face-to-face orientation during close contact which means this pattern had a lower infection risk via close contact. Probability of close contact decreased exponentially with the increasing distance between two students' cubicles. Data on human behaviour during close contact is helpful for infection risk analysis and infection control and prevention.

Clozapine-induced acute interstitial nephritis

Acute interstitial nephritis is a common cause of acute kidney injury. Acute interstitial nephritis is most commonly induced by drug although the cause may also be infective, autoimmune, or idiopathic. Although eosinophilia and eosinophiluria may help identify this disease entity, the gold standard for diagnosis remains renal biopsy. Prompt diagnosis is important because discontinuation of the culprit drugs can reduce further kidney injury. We present a patient with an underlying psychiatric disorder who was subsequently diagnosed with clozapine-induced acute interstitial nephritis. Monitoring of renal function during clozapine therapy is recommended for early recognition of this rare side-effect.

Anti-müllerian hormone and ovarian reserve in systemic lupus erythematosus

OBJECTIVE

To study the level of anti-müllerian hormone (AMH) and its relationship to age and previous exposure to cyclophosphamide (CYC) in patients with systemic lupus erythematosus (SLE).

METHODS

Consecutive female patients ages 18-52 years who had menses at least once during the preceding 12 months and fulfilled ≥4 American College of Rheumatology criteria for SLE were recruited. AMH was determined using an enzyme-linked immunosorbent assay (ELISA) kit. Serum AMH levels were compared in patients with and without previous use of immunosuppressive agents. The relationship of the AMH level to the patient's age and CYC exposure was studied by linear regression and receiver operating characteristic (ROC) curve analysis.

RESULTS

A total of 216 patients were studied (mean±SD age 35.1±10.1 years, mean±SD SLE duration 7.6±5.9 years). The mean±SD AMH level was significantly lower in patients previously exposed to CYC therapy than in those who had not been exposed after adjustment for age (1.58±2.92 versus 1.73±2.11 ng/ml; P=0.04). The median time interval between the AMH assay and the last dose of CYC administered was 6.7 years (interquartile range 3.4-8.5). AMH levels in users versus nonusers of other immunosuppressive agents, including mycophenolate mofetil, azathioprine, and the calcineurin inhibitors, were not statistically different. Linear regression revealed increasing age (beta -0.32, P=0.02) and each 5 gm of CYC exposure (beta -0.28, P=0.047) were independently associated with a lower AMH level. In patients ages 30 years and younger, a cumulative CYC dose cutoff of 5.9 gm yielded a sensitivity of 0.75 and a specificity of 0.80 for the prediction of undetectable AMH level on ROC curve analysis.

CONCLUSION

AMH is a sensitive marker for ovarian damage due to previous CYC exposure in women with SLE.

Immune response towards the amino-terminus of desmoglein 1 prevails across different activity stages in nonendemic pemphigus foliaceus

BACKGROUND

Pemphigus foliaceus (PF) is a blistering skin disease mediated by antibodies to desmoglein (Dsg) 1. The two major subtypes are nonendemic and endemic PF. A previous study in endemic PF demonstrated that changes in antibody epitope could modulate disease relapse and remission.

OBJECTIVES

To characterize the frequency of immunoreactivity to various Dsg1 extracellular (EC) domains in nonendemic PF and to study if there is any change in epitope profile across various activity stages.

METHODS

Sera from 34 patients with nonendemic PF were selected. To map the conformational epitopes by immunoprecipitation-immunoblotting, we constructed five Dsg1/Dsg2 domain-swapped molecules, with each molecule representing one EC domain of Dsg1 on a backbone of Dsg2.

RESULTS

Dsg1 EC1, EC2, EC3, EC4 and EC5 domains were recognized by 88%, 50%, 13%, 22% and 0% of active PF sera, respectively. Immunoreactivity to EC3 or EC4 often cosegregated with that to either EC1 or EC2. Longitudinal follow-up of 21 patients with PF for a median of 16 months revealed that, in most cases, immunoreactivity to the amino-terminus of Dsg1 persisted across various activity stages; only two patients lost their EC1 reactivity upon remission and changed their major epitope(s) to EC2 ± EC3.

CONCLUSIONS

Most of the anti-Dsg1 antibodies in nonendemic PF bind to the amino-terminus of Dsg1, a region critical for intercellular adhesion of cadherins, and this skewed amino-terminal immunoreactivity prevails across various activity stages in most patients, even upon remission. These findings are valuable for understanding the biology of Dsg-mediated cellular adhesion as well as for the development of epitope-based monitoring and therapeutic strategies.

Glomeruloid haemangioma with cerebriform morphology in a patient with POEMS syndrome

A 40-year-old Chinese man presented with sensorimotor polyneuropathy, IgAlambda paraprotein, osteosclerotic bone lesions, hypertrichosis, and impotence with decreased testosterone and raised prolactin level. POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy and skin changes) syndrome was diagnosed and he was treated with melphalan and prednisolone. After chemotherapy, other manifestations of POEMS syndrome developed, such as multiple haemangiomas over the chest and neck region, splenomegaly and generalized oedema. One haemangioma had a peculiar clinical morphology, similar to the appearance of cerebral gyri. Skin biopsy confirmed the diagnosis of glomeruloid haemangioma. Chemotherapy was then switched to cyclophosphamide and prednisolone, resulting in further improvement in muscle power and hypertrichosis. To our knowledge, this is the first report on a clinically distinctive morphology of glomeruloid haemangioma, and its recognition may increase the index of suspicion for early skin biopsy.

Rice-body formation in atypical mycobacterial tenosynovitis and bursitis: findings on sonography and MR imaging

OBJECTIVE

This article describes rice bodies found in patients with atypical mycobacterial tenosynovitis and bursitis, emphasizing the sonographic and MR imaging appearances of these small bodies.

CONCLUSION

Rice bodies occur in patients with atypical mycobacterial tenosynovitis and bursitis. When small, rice bodies are better visualized on MR imaging than on sonography, allowing the radiologist to consider appropriate diagnoses.

Tarsal tunnel syndrome caused by talocalcaneal coalition

Tarsal tunnel syndrome caused by talocalcaneal coalition is uncommon. We presented the ultrasonography (US) and magnetic resonance imaging findings of this disease. This is, to our knowledge, the first case report describing the US findings in tarsal tunnel syndrome caused by talocalcaneal coalition.

Internal fixation of valgus-impacted humeral head fractures using the screw-wiring technique

Between February 1996 and July 2000 eight patients (ages 35-74 years) with nine severely impacted humeral head fractures were operated on with the aim of preserving the humeral heads. Patients were treated surgically with open reduction, autologous bone grafting, and internal fixation with a screw-wiring technique. There were no complications and all patients were satisfied with the results. After 10-63 months there was no evidence of nonunion, arthritis, avascular necrosis, or loosening of implants. The mean Constant score was 83 (66-97) points. Results of this study support the observation that four-part valgus-impacted humeral head fractures without significant lateral displacement have a low incidence of avascular necrosis.

Testicular sperm extraction combined with intracytoplasmic sperm injection in the treatment of men with persistent azoospermia postchemotherapy

BACKGROUND

Men who remain azoospermic long after undergoing chemotherapy have generally been considered sterile. The authors report their experience with testicular sperm extraction (TESE) combined with intracytoplasmic sperm injection (ICSI) applied to azoospermic men who previously received chemotherapy for a variety of indications.

METHODS

Among 231 cycles in 198 patients who underwent TESE-ICSI for nonobstructive azoospermia from 1995 to 2000, 20 TESE procedures in 17 patients who previously received chemotherapy were identified. All TESE procedures were performed with microsurgical control under local anesthesia with sedation or general anesthesia. The pretreatment hormonal profile, histology of testicular biopsies, and outcomes of TESE-ICSI in this subgroup of patients were analyzed.

RESULTS

The mean patient age was 37.4 years (range, 28-54 years), and the mean follicle-stimulating hormone level was 21.8 mIU/mL (range, 7.1-43.1 mIU/mL). The mean age for female partners was 33.5 years (range, 22-43 years). Six patients had received chemotherapy for Hodgkin lymphoma (34%), four patients had received chemotherapy for testicular neoplasm (24%), two patients had received chemotherapy for non-Hodgkin lymphoma (12%), two patients had received chemotherapy for leukemia (12%), one patient had received chemotherapy for Wilms tumor (6%), one patient had received chemotherapy for mediastinal germ cell tumor (6%), and one patient had received chemotherapy for nephrotic syndrome (6%). Three patients (18%) received additional radiation therapy. The mean interval from chemotherapy to TESE was 16.3 years (range, 6-34 years). All patients had at least two semen analyses to confirm azoospermia. A total of 20 attempts of TESE-ICSI were performed (mean, 1.2 attempts per patient). Testicular histology revealed Sertoli cell-only pattern in 76% of patients. The remaining 24% of patients had hypospermatogenesis as their most advanced spermatogenic pattern. Among the men with Sertoli cell-only pattern, 23% had sperm retrieved by TESE. Sperm retrieval was accomplished in 9 of 20 attempts (45%), with biochemical pregnancy after sperm retrieval in 4 of 9 couples (45%) and clinical pregnancy in 3 of 9 couples (33%). Live deliveries were achieved in 2 of 9 couples (22%). Two healthy boys and one girl were delivered. No correlation was noted between the outcome of TESE-ICSI and the underlying conditions that were treated with chemotherapy nor with the chemotherapeutic agents used.

CONCLUSIONS

Using TESE-ICSI, sperm retrieval leading to pregnancy and the delivery of healthy children is possible for men with long-standing azoospermia after chemotherapy. The prognosis for sperm retrieval was not influenced clearly by the chemotherapy regimen or the disease treated. Diagnostic biopsy also was of limited value in predicting the outcome of sperm retrieval. Despite prolonged nonobstructive azoospermia after undergoing chemotherapy, men no longer should be considered sterile in the era of advanced assisted reproductive techniques.

FGF-2 immunoreactivity in adult rat ependyma and choroid plexus: responses to global forebrain ischemia and intraventricular FGF-2

Fibroblast growth factor 2 (FGF-2) immunoreactivity (IR) was examined in the ependyma and choroid plexus (CP) of lateral and third ventricles in normal adult rats, as well as in response to transient forebrain ischemia (TFI) and exogenous FGF-2 delivered intraventricularly for several days by osmotic pump. Similar patterns of FGF-2 IR were seen in the CP epithelia of both lateral and third ventricles, as well as in ependymal cells of the third ventricle and along lateral sides of the lateral ventricles. Consistent staining was seen along the apical aspect of epithelial cells facing the cerebrospinal fluid (CSF). Cytoplasmic staining was seen in the absence of ischemia, and was dramatically reduced in response to TFI. FGF-2 treatment followed by TFI resulted in sustained FGF-2 IR within CP and ependymal cells, supporting the idea that these tissues are involved in synthesis and secretion of growth factors into the CSF. In contrast, along the medial sides of the lateral ventricles, adjacent to brain structures such as the hippocampus, consistent staining was seen along the basal aspect of the ependymal cells. We propose that at least some regions of ependyma may function to transport molecules such as FGF-2 directly into the underlying brain parenchyma.

Diagnostic and therapeutic testis biopsy

Testicular biopsy has been traditionally used as a diagnostic tool in the management of infertility. With the advent of assisted reproductive technology, testicular biopsy is now used therapeutically to retrieve sperm for intracytoplasmic sperm injection (ICSI). The feasibility of testicular sperm extraction for ICSI is reviewed in this article. Although less invasive techniques such as testicular fine needle aspiration and percutaneous needle biopsy are efficacious, particularly in cases of obstructive azoospermia, studies in the current literature support that open testicular biopsy is a more reliable method to obtain testicular specimen. Different measures to reduce the complication rate of open testicular biopsy, including the application of microsurgical techniques, are addressed here. Other areas of recent development related to testicular biopsy that are reviewed include processing of testicular tissue, cryopreservation of retrieved spermatozoa, in vitro maturation of spermatozoa, and microinjection of immature spermatogenic precursor cells.

Nonobstructive azoospermia

Nonobstructive azoospermia (NOA) remains a challenging condition in reproductive medicine to manage. The genetic basis of NOA related to partial deletions of the Y-chromosome has been intensely investigated. Such information is of prognostic value and allows more insightful genetic counseling of couples who opt for assisted reproductive technology. Testicular sperm extraction (TESE) combined with intracytoplasmic sperm injection has allowed many men with NOA to father their own biologic children. Although studies in the current literature support open testicular biopsy as the most reliable method to obtain testicular sperm, less invasive techniques such as testicular fine-needle aspiration and percutaneous needle biopsy are feasible alternatives in selected groups of patients. Measures to improve the efficacy of TESE, including the application of microsurgical techniques, are addressed. Other recent developments related to the management of NOA reviewed include processing of testicular tissue, cryopreservation of retrieved spermatozoa, in-vitro maturation of germ cells and microinjection of immature spermatogenic precursor cells.

Short-term complications of pubovaginal sling procedure for genuine stress incontinence in women

OBJECTIVES

To evaluate the complication rate intraoperatively and within the first 30 postoperative days of the pubovaginal sling procedure.

METHODS

From January 1992 to September 1996, we prospectively analyzed 90 women with type II and III genuine stress incontinence (age 38 to 84 years, average Valsalva leak point pressure 57.5 cm H2O) who underwent the pubovaginal sling procedure at our institute. Sixty percent of patients had no previous surgical treatment for their incontinence. Thirty-three percent of our patients have significant comorbidity (chronic obstructive lung disease, diabetes, coronary artery disease, peripheral vascular disease).

RESULTS

The complication rate within the first 30 postoperative days was 19%, which included pneumonia (1.1%), deep venous thrombosis (1.1%), urinary retention (3.3%), wound infection (7.7%), intraoperative bladder laceration (3.3%), urinary tract infection (1.1%), and superficial thrombophlebitis (1.1%). A similar complication rate was noted among our patients with no previous surgical treatment for their incontinence.

CONCLUSIONS

The complication rate of our prospective series of pubovaginal sling procedures was comparable to that of the other surgical procedures for genuine stress incontinence reported in the literature. We conclude that even though the pubovaginal sling procedure is a relatively complex surgery, in view of its satisfactory long-term success rate reported in the recent literature, pubovaginal sling procedure should also be considered a primary surgical treatment for genuine stress incontinence in a selected population of women.

Attitudes of Hong Kong high school students towards the nursing profession

The increased development of hospital services in Hong Kong over the last decade has given rise in the demand for more recruits to join the nursing profession. Despite the advancement in education and the improvement in the working conditions, the problems of attracting sufficient new recruits remain critical. This study aimed to examine high school students' attitudes towards the nursing profession and to identify the contributing factors affecting shortage of nurses within the context of Hong Kong. A convenience sample of 375 high school students was recruited. A questionnaire was used to measure their knowledge, attitudes and intention to study nursing. Descriptive and inferential statistics were used to describe their career preferences and to compare knowledge, attitudes and intention scales between gender and nursing exposure groups. Results indicated that the students were generally knowledgeable about nursing but were reluctant to pursue nursing as a career. However, students who were socially acquainted with a nurse demonstrated a slightly more positive attitude towards nursing and slightly higher intention to pursue nursing as a career compared with those having no social acquaintance with a nurse. Implications for promotion of nursing profession and limitations of the study were discussed.

Jasmine green tea epicatechins are hypolipidemic in hamsters (Mesocricetus auratus) fed a high fat diet

These studies were designed to test the hypolipidemic activity of green tea epicatechins (GTE) isolated from jasmine green tea. In Experiment 1, three groups of hamsters were given a semisynthetic diet containing 200 g lard/kg and 1 g cholesterol/kg for 4 wk. The control group received distilled water, and the other two groups received either 15 g/L green tea water extract (GTWE) or 5.0 g/L GTE solution. Both the GTWE and GTE groups had lower concentrations of serum total cholesterol (TC) and triacylglycerols (TG) than the controls (P < 0.05). In Experiment 2, four groups of hamsters received tap water as the drinking fluid, but they were given the same high fat and cholesterol diet supplemented with 0 (control), 1.1, 3.4 or 5.7 g GTE/kg diet. The hypolipidemic effect of jasmine GTE was dose dependent. In Experiment 3, the time-course of changes in serum TC and TG was monitored in hamsters given the high fat diet supplemented with 5.7 g GTE/kg in comparison with that of controls. The hypolipidemic effects of dietary GTE were evident after feeding for 2 wk. Dietary supplementation of GTE did not affect liver fatty acid synthase. However, GTE-supplemented hamsters had higher fecal excretions of total fatty acids, neutral sterols and acidic sterols compared with the control group. In Experiment 4, hamsters were fed nonpurified diet; the control group drank distilled water, and the GTE group drank distilled water containing 5.0 g GTE/L. No differences in activities of 3-hydroxy-3-methyl glutaryl coenzyme A reductase and intestinal acyl CoA:cholesterol acyltransferase were observed. This study suggests that the hypolipidemic activity of GTE is not due to inhibition of synthesis of cholesterol or fatty acid but is most likely mediated by its influence on absorption of dietary fat and cholesterol.

Socio-cultural perspectives on the image of nursing: the Hong Kong dimension

Using structured interviews a study was undertaken with 19 high school students in Hong Kong to elicit their perceptions of nursing as a profession. The study also sought to gauge the extent of the students' intentions on pursuing a career in nursing. Responses were content analysed to determine the extent of knowledge and understanding held, intentions on choosing nursing as a career and their reasons. Findings suggest the image of nursing to be poor and that nursing as a career is far from desirable amongst the teenagers of Hong Kong. The reasons appear to be related to the notion of monetary rewards and status within the Hong Kong community. There is also a lack of knowledge as to what nurses do. The implications of such findings include the lost potential for recruitment of candidates of high calibre with a lot to offer the profession and their society. It suggests the need for the profession to find ways of publicizing and marketing the positive aspects with elements of realism which the general population in that part of the world could relate to more readily.

Regulation of the collagenase-3 receptor and its role in intracellular ligand processing in rat osteoblastic cells

We have previously described a specific, saturable receptor for rat collagenase-3 in the rat osteosarcoma cell line, UMR 106-01. Binding of rat collagenase-3 to this receptor is coupled to the internalization and eventual degradation of the enzyme and correlates with observed extracellular levels of the enzyme. In this study we have shown that decreased binding, internalization, and degradation of 125I-rat collagenase-3 were observed in cells after 24 h of parathyroid hormone treatment; these activities returned to control values after 48 h and were increased substantially (twice control levels) after 96 h of treatment with the hormone. Subcellular fractionation studies to identify the route of uptake and degradation of collagenase-3 localized intracellular accumulation of 125I-rat collagenase-3 initially in Golgi-associated lysosomes and later in secondary lysosomes. Maximal lysosomal accumulation of the radiolabel and stimulation of general lysosomal activity occurred after 72 h of parathyroid hormone treatment. Preventing fusion of endosomes with lysosomes (by temperature shift, colchicine, or monensin) resulted in no internalized 125I-collagenase-3 in either lysosomal fraction. Treatment of UMR cells with the above agents or ammonium chloride decreased excretion of 125I-labeled degradation products of collagenase-3. These experiments demonstrated that degradation of collagenase-3 required receptor-mediated endocytosis and sequential processing by endosomes and lysosomes. Thus, parathyroid hormone regulates the expression and synthesis of collagenase-3 as well as the abundance and functioning of the collagenase-3 receptor and the intracellular degradation of its ligand. The coordinate changes in the secretion of collagenase-3 and expression of the receptor determine the net abundance of the enzyme in the extracellular space.

The temporal profile and morphologic features of neuronal death in human stroke resemble those observed in experimental forebrain ischemia: the potential role of apoptosis

Although neuronal death has been studied in experimental models of ischemia, the precise mechanisms regulating cell death remain unclear. Furthermore, the timing and pattern of neuronal death in human stroke has not been extensively studied. To further our understanding of ischemia-induced neuronal death, we examined the temporal profile of histochemical and morphologic characteristics of hippocampal neuronal death following experimental forebrain ischemia and compared these findings to human brain specimens obtained from subjects suffering cerebral infarction. Transient forebrain ischemia (TFI) was induced in normothermic adult rats by bilateral carotid artery occlusion combined with hypotension. Animals were sacrificed at 6, 12, 18, 24, 48, and 72 h and 7, 14, and 28 days following ischemia (n = 4 at each time point). Experimental tissue was analyzed using light and electron microscopy as well as TUNEL histochemistry. A total of 27 human brain specimens with neuropathological confirmation of ischemic damage and appropriate controls were also examined using light microscopy and TUNEL histochemistry. Dense TUNEL staining in hippocampal CA-1 neurons was present at 48 and 72 h following experimental ischemia. Prior to these times, little or no nuclear staining was noted and after 72 h nuclear staining diminished rapidly. Ultrastructural findings at these time points demonstrated many features similar to those seen in cells undergoing apoptosis, such as cell shrinkage with increased electron density, chromatin condensation with formation of heterochromatin, intact plasma membranes, and intact intracellular organelles. In a similar fashion, human stroke specimens during the subacute period showed dense nuclear TUNEL staining in penumbral neurons, whereas in the acute or chronic stages little or no staining was noted. Our results demonstrate that the timing of morphologic changes and TUNEL histochemistry following human stroke resembles that observed in experimental TFI. Furthermore, neuronal death in both experimental ischemia and human stroke share several features characteristic of apoptotic cell death.

Subgaleal hemorrhage in a premature infant with congenital diaphragmatic hernia following vacuum-assisted delivery

An infant with congenital diaphragmatic hernia was delivered by vacuum extraction, with a resultant subgaleal hemorrhage that excluded him from ECMO. The literature regarding vacuum-assisted delivery and birth trauma is reviewed in the context of congenital anomalies that may require ECMO support, and recommendations for perinatal management are suggested.

Priapism secondary to penile metastasis: a report of two cases and a review of the literature

Malignancy metastasis to the penis is an uncommon clinicopathological entity. We present two cases of malignant priapism following penile metastasis, in which the diagnosis was established by core needle biopsy of the corpus cavernosum. Primary tumors were urothelial carcinoma of the urinary bladder in one case (the patient having concomitant high-grade prostatic adenocarcinoma) and prostatic adenocarcinoma in the other. The clinicopathological features of 51 previously reported cases of penile metastasis in the recent literature are reviewed.

Priapism secondary to penile metastasis: a report of two cases and a review of the literature

Malignancy metastasis to the penis is an uncommon clinicopathological entity. We present two cases of malignant priapism following penile metastasis, in which the diagnosis was established by core needle biopsy of the corpus cavernosum. Primary tumors were urothelial carcinoma of the urinary bladder in one case (the patient having concomitant high-grade prostatic adenocarcinoma) and prostatic adenocarcinoma in the other. The clinicopathological features of 51 previously reported cases of penile metastasis in the recent literature are reviewed.

Non-English speaking background high school students' attitudes towards the nursing profession

Australia is a multicultural nation with its population coming from over 120 different cultural backgrounds. With the arrival of new immigrants from Southeast Asia, China, Korea and Lebanon over the last 20 years, issues such as the recruitment of bilingual and cross-cultural knowledgeable nurses have become a high priority within the health care system. However, recruiting these skilled professionals has been difficult. This study aimed to examine (1) non-English speaking background (NESB) high school students' career preferences in relation to nursing; and (2) whether nursing is perceived differently by the Korean, Lebanese, Vietnamese and mainland Chinese high school students. A convenience sample of 162 NESB high school students with parents from Korea, Lebanon, Vietnam and China was recruited from Sydney, New South Wales, Australia. Data were collected by a questionnaire to measure students' knowledge about, attitudes towards and intention to study nursing and their demographic details. Descriptive and inferential statistics were used to describe students' demographic background, their career preference and to compare knowledge, attitudes and intention scales among the NESB groups. Results indicated that less than 10% of students included nursing among their preferred career options. Korean students scored lower than the other NESB groups on attitude and intention towards nursing. The findings provide clues as to how nursing can be better promoted to NESB school leavers. Limitations of the study were discussed and recommendations were suggested for future research.

Primary non-Hodgkin's lymphoma of the nose and nasopharynx: clinical features, tumor immunophenotype, and treatment outcome in 113 patients

PURPOSE

To study the clinical features and outcome for primary non-Hodgkin's lymphomas of the nose/nasopharynx (NNP-NHLs) according to immunophenotype.

PATIENTS AND METHODS

One hundred thirteen Chinese patients with primary NNP-NHLs that belonged to the categories E, F, G, or H according to the Working Formulation (WF), with full immunophenotypic data and complete clinical follow-up data, were analyzed in this retrospective study.

RESULTS

Ninety (79.6%) patients had localized (stage I or II) disease, while 23 (20.4%) had stage III or IV disease. The lymphomas in 51 (45.1%), 24 (21.3%), and 38 (33.6%) patients showed natural killer (NK)/T- (CD56-positive), T-cell, and B-cell immunophenotype, respectively. Seventy-three patients (65.8%) achieved a complete remission, of whom 34 (46.6%) subsequently relapsed. The median follow-up time for those alive was 88 months. The 5-year actuarial disease-free and overall survival rates were 34.4% and 37.9%, respectively. Multivariate analysis showed that only stage and immunophenotype were significant for survival. NK/T lymphomas were distinctive among the three immunophenotypes in the following aspects: the highest male-to-female ratio, more frequent involvement of the nasal cavity alone, higher risk of dissemination to the skin, more frequent development of hemophagocytic syndrome, and the worst prognosis (overall median survival, 12.5 months).

CONCLUSION

The three immunophenotypes studied are shown to exhibit different clinical patterns. Since the NK/T phenotype carries the worst prognosis, patients who present with NNP-NHL should have their tumors analyzed for CD56 expression.

Polycythemia vera in Chinese patients: thirty-six years of experience

Forty-one patients with polycythemia vera (PV) according to the PVSG criteria were analysed retrospectively from January 1960 to March 1996. There were 23 male and 18 female patients with a median follow-up of 66.5 months (3-431 months). Median age was 62 (range: 37-85). The median hemoglobin level at diagnosis was 18.8 g/dl. Four patients were treated by venesection alone, 20 patients received hydroxyurea and intermittent venesection, 3 were treated with radioactive phosphorus alone, and 14 had both hydroxyurea and radioactive phosphorus. During the course of illness, 14 patients (34%) developed a total of 19 thrombotic events. Of the thrombotic events, 16 were arterial and 3 were venous. Two patients had both arterial and venous thrombosis sequentially. The probability of thrombosis-free survival after treatment was 83% at 10 years and 73% at 20 years. One patient developed post-polycythemic myeloid metaplasia 24 months after diagnosis. Of 17 patients exposed to radioactive phosphorus, only 1 developed secondary acute myeloid leukemia (AML) 9 years afterwards. Of the 20 patients treated with hydroxyurea for a median duration of 63.5 months (2-130 months), there is no case of secondary malignancy. Overall survival was 83% at 10 years and 62% at 20 years. In conclusion, PV in Chinese is a relatively benign disease with a low risk of thrombosis as compared to Caucasian patients. Hydroxyurea has a very low risk of secondary leukemia and is a safe drug to use in Chinese patients with PV.

Antioxidant activity of natural flavonoids is governed by number and location of their aromatic hydroxyl groups

We studied antioxidant activity of five natural flavonoids in canola oil, an emulsion, and rat red blood cell membrane. In the canola oil heated at 105 degrees C, myricetin most effectively attenuated lipid oxidation, followed by quercetin, morin and kaempferol in a decreasing order. When the emulsion containing canola oil was incubated at 54 degrees C, quercetin was most protective against lipid oxidation, followed by kaempferol, myricetin and morin in a decreasing rank. Apigenin demonstrated no antioxidant activity in either the canola oil or the emulsion. Of the flavonoids tested, quercetin was the best in quenching free radical chain reaction in rat red blood cell membrane. The antioxidative characteristics of these flavonoids was determined by multiple factors including the system used, the hydrophobicity, and the total number and the location of aromatic hydroxyl groups. We conclude that myricetin is an effective antioxidant in canola oil, while quercetin is an effective protector against lipid oxidation in the cell membrane.

7-Nitroindazole: a selective inhibitor of penile erection: an in vivo study in a rat animal model

OBJECTIVES

The neuronal isoform of nitric oxide synthase (nNOS) has been localized in neurons innervating the penis and is believed to be an important mediator of erection. Using the selective inhibitor 7-nitroindazole (7-NI), we evaluated the possible role of nNOS in penile erection using a rat animal model.

METHODS

Eighteen Sprague-Dawley rats were divided into three study groups. A sham group (n = 6) received the vehicle arachis oil, a low-dose group received 5 mg/kg (n = 6), and a high-dose group received 50 mg/kg (n = 6) of 7-NI prior to measurement of blood pressure and cavernous nerve stimulation-induced rise in intracavernous pressure.

RESULTS

A dose-dependent inhibition of erection by 7-NI was seen. Control animals had an intracavernous pressure rise of 55.5 +/- 4.0 cm H2O, whereas the low-dose group had 26.5 +/- 2.8 cm H2O and the high-dose group had 6.2 +/- 2.1 cm H2O. A partial recovery of erection was seen in the low- and high-dose groups after 3 hours. Blood pressure was unaffected by 7-NI administration.

CONCLUSIONS

7-NI induced a reversible, dose-dependent inhibition of erection without affecting blood pressure. This in vivo study provides further evidence of the role played by nNOS in erection.

The regulation and regulatory role of collagenase in bone

Interstitial collagenase plays an important role in both the normal and pathological remodeling of collagenous extracellular matrices, including skeletal tissues. The enzyme is a member of the family of matrix metalloproteinases. Only one rodent interstitial collagenase has been found but there are two human enzymes, human collagenase-1 and -3, the latter being the homologue of the rat enzyme. In developing rat and mouse bone, collagenase is expressed by hypertrophic chondrocytes, osteoblasts, and osteocytes, a situation that is replicated in a fracture callus. Cultured osteoblasts derived from neonatal rat calvariae show greater amounts of collagenase transcripts late in differentiation. These levels can be regulated by parathyroid hormone (PTH), retinoic acid, and insulin-like growth factors, as well as the degree of matrix mineralization. Much of the work on collagenase in bone has been derived from studies on the rat osteosarcoma cell line, UMR 106-01. All bone-resorbing agents stimulate these cells to produce collagenase mRNA and protein, with PTH being the most potent stimulator. Determination of secreted levels of collagenase has been difficult because UMR cells, normal rat osteoblasts, and rat fibroblasts possess a scavenger receptor that removes the enzyme from the extracellular space, internalizes and degrades it, thus imposing another level of control. PTH can also regulate the abundance of the receptor as well as the expression and synthesis of the enzyme. Regulation of the collagenase gene by PTH appears to involve the cAMP pathway as well as a primary response gene, possibly Fos, which then contributes to induction of the collagenase gene. The rat collagenase gene contains an activator protein-1 sequence that is necessary for basal expression, but other promoter regions may also participate in PTH regulation. Thus, there are many levels of regulation of collagenase in bone perhaps constraining what would otherwise be a rampant enzyme.

The cytoplasmic droplet of rat epididymal spermatozoa contains saccular elements with Golgi characteristics

The cytoplasmic droplet of epididymal spermatozoa is a small localized outpouching of cytoplasm of the tail of unknown significance. EM revealed flattened saccular elements as the near exclusive membranous component of the droplet. Light and electron microscopic immunolabeling for Golgi/TGN markers showed these saccules to be reactive for antibodies to TGN38, protein affinity-purified alpha 2,6 sialyltransferase, and anti-human beta 1,4 galactosyltransferase. The saccules were isolated by subcellular fractionation and antibodies raised against this fraction immunolabeled the saccules of the droplet in situ as well as the Golgi region of somatic epithelial cells lining the epididymis. The isolated droplet fraction was enriched in galactosyltransferase and sialyltransferase activities, and endogenous glycosylation assays identified the modification of several endogenous glycopeptides. EM lectin staining in situ demonstrated galactose and N-acetyl galactosamine constituents in the saccules. Endocytic studies with cationic and anionic ferritin as well as HRP failed to identify the saccules as components of the endocytic apparatus. Epididymal spermatozoa were devoid of markers for the ER as well as the Golgi-associated coatamer protein beta-COP. It is therefore unlikely that the saccular elements of the droplet participate in vesicular protein transport. However, the identification of Golgi/TGN glycosylating activities in the saccules may be related to plasma membrane modifications which occur during epididymal sperm maturation.

Site-directed mutagenesis of the -10 region of the lacUV5 promoter. Introduction of dA4.dT4 tract suppresses open complex formation

Homopolymeric dAn.dTn sequences, where n is 4 or greater, have special properties leading to increased duplex stability and DNA bending. The lacUV5 promoter was used to examine the functional consequences of changing the -10 TATAAT consensus sequence to the sequence TAAAAT. The transversion mutation at the underlined site was accomplished with site-directed mutagenesis using translation termination as the selection procedure. For free DNA, structural differences at the 5' and 3' junction regions of the dA4.dT4 tract can be readily detected by DNase I digestion. However, site binding by Escherichia coli RNA polymerase appeared unaltered by the TAAAAT sequence since identical DNase I footprints were obtained for the lacUV5 and mutant promoters. Binding competition studies under different ionic strengths revealed a significant reduction in mutant promoter open complex formation relative to the lacUV5 promoter. Mutant promoter open complexes also dissociated faster and to a greater extent than the corresponding lacUV5 promoter open complexes when challenged with heparin or a combination of heparin and increased KCl concentration. Consequently, mutant promoter open complexes appear less stable than lacUV5 promoter open complexes.

Site-directed chemical modification for probing DNA-protein interactions. Osmium tetroxide modification of the -10 site of the lacUV5 promoter enhances open complex formation

A new experimental approach, site-directed chemical modification, was used to explore relationships between RNA polymerase-promoter interactions and function. For this study, the lacUV5 promoter with an exposed -10 thymine on the non-template strand was constructed. Osmium tetroxide was selected as the thymine modifying reagent. Modification occurred predominantly at the exposed -10 T with 5-fold less reactivity at the -12 T residue. The isolated modified strand was used to reconstitute a lacUV5 promoter with -10 (-12) adducts. OsO4 modification at both the -10 and -12 positions of the lacUV5 promoter significantly enhances Escherichia coli RNA polymerase-promoter open complex formation relative to the unmodified promoter. DNase I cleavage sites at -7, -8, and -10 of the unmodified promoter were rendered insusceptible to scission in the modified promoter. However, no difference can be detected in the RNA polymerase footprints for unmodified versus modified open complexes. The latter are fully capable of productive transcription with comparable amounts of identical run-off transcripts to unmodified open complexes. A 16 degrees C reduction in Tm was found for a 14-base pair oligonucleotide duplex containing a single OsO4-bispyridine adduct. The latter result suggests that open complex formation appears to be enhanced due to promoter unpairing at the -10 (-12) adduct sites.

Nucleotide sequence and expression of the pyrC gene of Escherichia coli K-12

The pyrC gene of Escherichia coli K-12, which encodes the pyrimidine biosynthetic enzyme dihydroorotase, was cloned as part of a 1.6-kilobase-pair chromosomal fragment. The nucleotide sequence of this fragment was determined. An open reading frame encoding a 348-amino acid polypeptide (Mr = 38,827) was identified as the pyrC structural gene by comparing the amino acid composition predicted from the DNA sequence with that previously determined for the dihydroorotase subunit. The pyrC promoter was mapped by primer extension of in vivo transcripts. Transcriptional initiation was shown to occur within a region located 36 to 39 base pairs upstream of the pyrC structural gene. Pyrimidine availability appears to affect the use of the minor transcriptional initiation sites. The level of pyrC transcription and dihydroorotase synthesis was coordinately derepressed by pyrimidine limitation, indicating that regulation occurs, at least primarily, at the transcriptional level. Inspection of the pyrC nucleotide sequence indicates that gene expression is not regulated by an attenuation control mechanism similar to that described for the pyrBI operon and the pyrE gene. A possible mechanism of transcriptional control involving a common repressor protein is suggested by the identification of a highly conserved, operatorlike sequence in the promoter regions of pyrC and the other pyrimidine genes (i.e., pyrD and carAB) whose expression is negatively regulated by a cytidine nucleotide effector.

Nucleotide sequence and gene organization of ColE1 DNA

The primary structure of the plasmid ColE1 DNA has been determined. The plasmid DNA consists of 6646 base pairs (molecular mass of 4.43 MDa) and is 48.46% in GC content. The phi 80 trp insert of the composite plasmid of ColE1, pVH51, has also been determined. The determination of the nucleotide sequence of ColE1 DNA provides the basis for examining the relationships between the DNA sequence and the gene organization of the plasmid. The focus of this paper is to use this sequence data coupled with a review of the literature and our own work to examine the nine known functional regions of ColE1: imm (colicin E1 immunity), rep (replication function), inc (plasmid incompatibility and copy number control), bom (basis of mobility), rom (modulator of inhibition of primer formation by RNA I), mob (plasmid mobilization), cer (determinant for conversion of plasmid multimers to monomers), exc (plasmid entry exclusion), cea (structural gene for colicin E1), and kil (structural gene for the Kil protein).

The coupled use of 'footprinting' and exonuclease III methodology for RNA polymerase binding and initiation. Application for the analysis of three tandem promoters at the control region of colicin El

In order to determine the initiation site for three promoters P1, P2 and P3 (5' to 3') in close proximity in the colicin E1 control region we developed a new methodology that couples ternary complex formation and the analysis of the 3' border protected from exonuclease III digestion. The initiation of transcription could be detected by measuring the shift in the position of the 3' protected border when RNA polymerase moved from its binary complex position to its ternary complex position. The latter stops at a specific nucleotide because transcription is initiated with one or more NTPs missing. This approach, coupled with "footprinting", can also be used to decide whether the formation of an RNA polymerase binary or ternary complex at one site excludes or weakens binding at neighboring sites. The location of 3' protected borders reveals the formation of respective binary and ternary complexes at non-saturating RNA polymerase conditions, whereas at saturating conditions only the distal 3' boundary is seen and exonuclease cannot penetrate further. However, if "footprinting" reveals proximal 5' patterns this establishes that simultaneous binding has occurred on the same DNA fragment. The data showed that this was true for P1 and P3 which are only 8 nucleotides apart. P2 could only be detected at non-saturating conditions since it overlaps both P1 and P3. The evidence from the literature and this study establishes P1 as the true colicin E1 promoter with the possibility that supercoiling may eliminate any role for P2 and P3.

Mapping of RNA polymerase binding sites in R12 derived plasmids carrying the replication-incompatibility region and the insertion element IS1

Interactions between Escherichia coli RNA polymerase holoenzyme and three small plasmid DNAs (pSM1, pSM2, and pSM15) derived from the drug resistant factor R12 have been studied. These plasmids carry the copy number and incompatibility determinants, the origin of DNA replication and the rep gene(s) necessary for plasmid replication. They also contain the insertion element IS1 and the putative finO cistron. Thirteen DNA segments within the largest of the three plasmids (pSM2) were able to form either a binary and/or ternary complex with RNA polymerase. A unique strong binding site was mapped within the left end of IS1. Five binding sites were found within the rep-cop-inc region. Four of these are weak binding sites whereas the fifth does not form a stable binary complex and was detected by ternary complex formation. A strong binding site was located in the putative finO region whereas the remaining six binding sites are located in regions with unidentified genetic functions.

Nucleotide sequence determination of a strong promoter of the colicin E 1 plasmid. Analysis of restriction sites protected by RNA polymerase interactions before and after limited transcription

This paper presents the location and nucleotide sequence of a strong promoter of ColE 1. This promoter is of interest because of its greatly enhanced activity in the supercoiled state of the plasmid DNA (3) and its possible role in the maintenance of the plasmid replicon (4). This strong promoter is located at the restriction endonuclease Hae III f-h site 0.13 map units from the single EcoR 1 site proximal to the origin of DNA replication. The nucleotide sequence of the Hpa II l fragment of ColE 1 which contains this promoter has been determined. Initiation of transcription at this promoter occurred at two positions. Limited transcription by omitting one of the four nucleotide triphosphates allowed transcription to proceed to the fourth (-UTP) and to the twelfth (-CTP) nucleotides respectively. This was used to probe the interaction between RNA polymerase and the ColE 10.13 promoter by means of restriction cutting at the Hae III site at =27 and the Hha I site at +17. RNA polymerase binding alone blocks restriction cutting at the HAE III site but not at the Hha I site. Limited transcrption to the fourth nucleotide resulted in blocking at both sites. Transcription to the twelfth nucleotide resulted in partial cutting at the Hae III site and blocking at the Hha I site.