Digestive properties of the venom of the Australian Coastal Taipan, Oxyuranus scutellatus (Peters, 1867).

The digestive properties of Australian elapid snake venoms have not been studied to any great extent. To address this, the in vitro digestive properties of Oxyuranus scutellatus (Australian Coastal Taipan) venom were investigated in a simulation of the in vivo conditions using the parameters reported for the stomach of snakes and representative prey for this species. The amount of soluble protein released was measured over time using a bicinchoninic acid (BCA) assay. Dismembered mouse hindlegs were injected intramuscularly with 0.1 ml O. scutellatus venom (concentration 10 mg/ml) and maintained in a micro-anaerobic, acidic environment (pH approximately 1.2-1.7) at 25 degrees C. The bathing liquid was sampled every 24 h for 7 days, and assayed for soluble protein. Statistical analysis revealed that O. scutellatus venom increased the rate at which proteins were released when compared to a negative control suggesting the potential importance of envenomation in the digestion of whole prey.     

1,25(OH)2Vitamin D3 induces elevated expression of the cell cycle inhibitor p18 in a squamous cell carcinoma cell line of the head and neck

BACKGROUND: 1Alpha,25-dihydroxyvitamin D(3) [1,25(OH)(2) Vitamin D(3)] induces growth inhibition in squamous cell carcinoma (SCC) cell lines of the head and neck by arresting the cells in the G0/G1 phase of the cell cycle, probably due to an enhanced expression of p21, which could be demonstrated in other cell lines (JPPA, SCC9) before. In SCC25, a SCC cell line isolated from tongue, growth inhibition but no overexpression of p21 was detected. The retinoblastoma gene, as a direct target of G1 cyclin-CDK complexes, showed an obvious shift from the hyperphosphorylated to the hypophosphorylated form under 1,25(OH)(2)Vitamin D(3), which indicates that the growth inhibition takes place in the G0/G1 phase. To explore the possible pathway of growth inhibition in SCC25 we investigated other cell cycle inhibitors (p18, p19, p27). METHODS: Synchronized cells were treated with 1,25(OH)(2)Vitamin D(3) over 96 h. The cell cycle status and expression of cell cycle-regulating proteins was determined by fluorescence-activated cell sorting (FACS) and Western blotting. An overexpression of p18 in 1,25(OH)(2)Vitamin D(3) vs. ethanol-treated cells was determined until 30 h in SCC25. No influence was detectable on the expression of p27 and p19. CONCLUSION: One mechanism by which 1,25(OH)(2)Vitamin D(3) controls cell growth might be the upregulation of p21. As p21 was unsusceptible to 1,25(OH)(2)Vitamin D(3) in SCC25, other inhibiting proteins were necessary to be tested. The proven upregulation of p18 seems to be the responsible step for growth inhibition of 1,25(OH)(2)Vitamin D(3) in SCC25.     

Stability of human methanogenic flora over 35 years and a review of insights obtained from breath methane measurements.

BACKGROUND & AIMS: Breath methane measurements reflect the in situ activity of the methanogenic colonic flora. Thirty-five years ago we found that 34% of healthy adult subjects were methane producers (breath methane level >1 ppm above atmospheric methane levels). The current study presents a new survey of breath methane levels designed to determine if the activity of the methanogenic flora has changed over the past 35 years. In addition, we review insights into the methanogenic flora that have resulted from breath methane measurements. METHODS: The end-alveolar breath methane concentrations of 212 healthy adults living in the Minneapolis area were determined via gas chromatography. The influence of sex, age, and bowel movement frequency on methane production was assessed. RESULTS: The findings that 36.4% of participants were methane producers, with a mean methane concentration in these producers of 16.6 ppm, are strikingly similar to the values of 33.6% and 15.2 ppm observed 35 years ago. Neither sex nor age showed a statistically significant relationship to methane production. There was a negative correlation between frequency of bowel movements and breath methane concentration in methane producers. CONCLUSIONS: The activity of the methanogenic flora of healthy adults remained remarkably stable over the past 35 years despite widespread antibiotic use and dietary changes. A literature review revealed that many associations have been shown between methane production and clinical states, but it remains to be determined if methanogens actively influence human physiology or are simply a marker of colonic function.     

Breastfeeding by Aboriginal mothers in Perth

Objective: To document the breastfeeding practices of Aboriginal mothers delivering in Perth. Design and methods: A cohort of mothers was followed from the time of delivery for six months to obtain details of infant feeding practices. Subjects: A total of 455 mothers delivered during the study period and were asked to participate. A total of 425 mothers completed the initial questionnaire. Setting: The study was undertaken in six public hospitals in Perth, Western Australia. Data analyses: The data were analysed using spss . Breastfeeding duration was calculated using Kaplan–Meier survival analysis. Main outcome measures: Breastfeeding initiation and duration. Results: The mean age of the Aboriginal mothers was 21.8 years (range 14–39 years, SD 5.32) and the average gestational age was 38.3 weeks. Almost 50% of the mothers in the study delivered by Caesarean section. At discharge from hospital 89.4% (CI 86.6–92.1) of mothers were breastfeeding, declining to 58.8% (CI 53.5–64.1) at six months. When compared with non‐Aboriginal mothers, the Aboriginal breastfeeding rates were higher than the non‐Aboriginal average breastfeeding rates, but lower than the highest socioeconomic group. Conclusions: The breastfeeding rates of Aboriginal mothers are higher than for other Australians. This is despite the low maternal age and level of education and the high rates of low‐birth‐weight infants and Caesarean section among this population. The World Health Organization recommendation for infant feeding is exclusive breastfeeding until six months, but less than one‐third of Aboriginal mothers achieved this recommendation.     

Wound Botulism Associated with Black Tar Heroin

The incidence of wound botulism is increasing and the epidemiology of the disease is changing. The majority of new cases are associated with injection drug use, in particular, the use of Mexican black tar heroin. This case report and discussion of wound botulism illustrate the following important points: Dysphagia, dysphonia, diplopia, and descending paralysis, in association with injection drug use, should alert the treating physician to the possibility of wound botulism. In such patients, the onset of respiratory failure may be sudden and without clinically obvious signs of respiratory weakness. For the reported patient, maximum inspiratory force measurements were the only reliable indicator of respiratory muscle weakness. This is a measurement not routinely performed in the ED, but may prove essential for patients with suspected wound botulism. To minimize the effect of the botulinum toxin and to decrease length of hospital stay, antitoxin administration and surgical wound debridement should be performed early.     

A novel two-step method for the formation of tissue-engineered cartilage by mature bovine chondrocytes: the alginate-recovered-chondrocyte (ARC) method.

Most attempts to tissue-engineer cartilage have involved seeding of cultured cells into a biological or synthetic scaffold. We have developed a novel two-step culture approach that makes possible the in vitro formation of cartilaginous-like tissue by mature adult bovine chondrocytes without the aid of a synthetic matrix. The first step consists of culturing chondrocytes under conditions that maintain their rounded shape and their molecular phenotype as assessed by type II collagen and aggrecan production. This step was accomplished by culturing the isolated chondrocytes in alginate beads until the cells have reestablished a proteoglycan-rich cell-associated matrix (CM). The second step consists of culturing the cells with their CM, after recovery from the beads, on a tissue culture insert with a porous membrane. In this study, young adult bovine articular chondrocytes were cultured in alginate beads in the presence of 10% or 20% fetal bovine serum (FBS). After 7 days of culture, the alginate beads were dissolved by incubating the beads for 20 min in sodium citrate buffer, a calcium chelator. Following a brief centrifugation, the cells with their CM were recovered, resuspended in medium containing 10% or 20% FBS and seeded onto a tissue culture insert. After 1 week of culture on the insert, the individual cells with their CM progressively became incorporated into a mass of cartilaginous tissue. Culture with 20% FBS resulted in the best formation of tissues. These tissues, easily recovered from the insert, were then subjected to biochemical and histological analyses. The biochemical results showed that the chondrocytes remain phenotypically stable in the tissues. The de novo tissue has a relatively high ratio of PG/collagen. Histological examination of the tissue revealed it contained a cartilage-like matrix strongly stained with toluidine blue. This scaffold-free system appears ideal to study, in vitro, the development of transplantable cartilaginous tissue.     

Acetabular blood flow during Bernese periacetabular osteotomy: an intraoperative study using laser Doppler flowmetry.

BACKGROUND: The blood flow to the acetabular fragment is of some concern in juxtaarticular pelvic osteotomies used for the treatment of hip dysplasia. No direct measurements have determined the effect of the Bernese periacetabular osteotomy (PAO) on acetabular perfusion. METHODS: Acetabular perfusion was measured by means of laser Doppler flowmetry in 10 patients undergoing a PAO for symptomatic acetabular dysplasia. During the surgical procedure, the intraosseous high energy laser Doppler reliably depicts dynamic changes of small vessel blood flow. Measurements were performed after defined surgical steps to obtain sequential information on the blood perfusion of the acetabular fragment. RESULTS: After complete separation of the acetabular fragment, nine out of 10 patients had pulsatile signals, but the blood flow (BF) significantly decreased by 77%. Corrective positioning of the fragment induced no further drop of the BF signal but a loss of pulsatility in six patients. After a recovery period of about 30 min following preliminary fixation of the fragment, reestablishment of the pulsatile signal and an increase of the BF signal was seen. At termination of the surgical procedure, five out of eight patients, who could be followed throughout the whole procedure, showed a clear pulsatile signal in the supraacetabular area. Bleeding of the supraacetabular cancellous surface could be observed in all acetabula. CONCLUSION: Despite careful preservation of soft tissues during the surgical procedure, a significant reduction of the blood flow in the supraacetabular region has been observed. Nevertheless, a pulsatile signal in more than 60% of the fragments after fragment correction and an increasing signal during the recovery period showed ongoing blood perfusion indicating reversible changes in the measured supraacetabular area. All osteotomies healed within eight weeks without showing signs of necrosis during a minimum follow up of 1 year.     

Ritanserin in the treatment of alcohol dependence – a multi-center clinical trial

Four hundred and twenty-three alcohol dependent subjects were enrolled into a 12-week randomized, double-blind, placebo-controlled study to determine the safety and efficacy of the 5-HT₂ receptor antagonist, ritanserin (2.5 mg/day or 5 mg/day), in reducing alcohol intake and craving. All subjects received 1 week of single-blind placebo prior to randomization into the 11-week double-blind phase. Additionally, all subjects received weekly individual sessions of manual-guided cognitive-behavioral therapy. Comparing the single-blind period with endpoint, there was approximately a 23% reduction in drinks/day; 34% fall in the total number of drinking days/week; 22% decrease in drinks/drinking day; and a 37% diminution in alcohol craving for all treatment groups. All treatment groups experienced a beneficial clinical outcome as assessed by the Clinical Global Impression Scale. There was, however, no significant difference between treatment groups on any of these measures of alcohol drinking, craving, or clinical outcome. Subjects were of relatively high social functioning at baseline, and this did not change significantly during treatment. Treatment groups did not differ significantly on either medication compliance or reported adverse events. Ritanserin treatment was associated with a dose-related prolongation of subjects’ QTc interval recording on the electrocardiogram. These results suggest that alcohol dependent subjects can show marked clinical improvement within a structured alcohol treatment program. These findings do not support an important role for ritanserin in the treatment of alcohol dependence. Received: 30 April 1996/Final version: 3 July 1996