MEASUREMENTS OF INTERFACE PRESSURE BETWEEN BODY SITES AND THE SURFACES OF FOUR SPECIALISED AIR MATTRESSES

SUMMARY Four specialised air mattresses had interface pressure measured under six body sites prone to pressure sores in 10 subjects, supine and sitting. The mattresses were the Clinirest (SSI) and FirstStep (KCI) continuous airflow mattress overlays, and Airwave (Pegasus) and Nimbus (Huntleigh) alternating pressure air mattresses. On the mattress overlays, average supine interface pressures were 2.33 kPa (scapula), 4.15 kPa (elbow), 1.94 kPa (sacrum) and 2.79 kPa (buttock), although they were higher at the occiput (7.97 kPa) and heel (11.7 kPa). The alternating pressure air mattresses had an average minimum interface pressure close to zero for three sites, rising to 4.28 kPa under the heel. Average maximum interface pressures were 8.61 kPa (occiput), 5.21 kPa (scapula), 4.90 (elbow), 4.85 kPa (sacrum), 4.61 kPa (buttock) and 13.2 kPa (heel). No accepted scientific method exists for comparing the two types of mattress. Our data suggest a clinical benefit at the occiput and heel (supine) in using an alternating pressure air mattress and a benefit in using a continuous airflow mattress overlay at other sites.     

Extended duration of herpes simplex virus DNA in genital lesions detected by the polymerase chain reaction.

To evaluate the utility of the polymerase chain reaction (PCR) for documenting herpes simplex virus (HSV) in persons with reactivated genital lesions viral isolation was compared with a recently developed PCR method. Three women experiencing four episodes of recurrent genital herpes were followed for 10 days per episode with daily examination and duplicate swabs of the lesions, one for HSV culture and one for PCR. HSV type 2 was cultured from three of four episodes and the mean duration of viral isolation from recurrent genital lesions was 2.6 days. PCR detected HSV DNA from lesion swabs during all four episodes, and HSV DNA was positive for an average of 6.8 days. HSV DNA was demonstrated in ulcerative lesions on 15 of 17 days versus 3 of 17 days by viral isolation (P less than .01). HSV PCR became negative when the lesions reepithelialized. These data suggest that PCR is a more sensitive measure of HSV infection than routine viral culture and that PCR detects the presence of HSV at times when culture is negative.     

Persistent Organochlorine Contaminants and Enantiomeric Signatures of Chiral Pollutants in Ringed Seals (Phoca hispida) Collected on the East and West Side of the Northwater Polynya, Canadian Arctic

To examine the influence of diet and age on organochlorine contaminant (OC) concentrations in two closely related ringed seal (Phoca hispida) populations enantiomeric fractions (EFs) of chiral contaminants and stable isotopes of nitrogen (δ¹⁵N) and carbon (δ¹³C) were measured along with OCs in ringed seals collected from the east and west side of the Northwater Polynya. Seals from these two locations were feeding at the same trophic level based on δ¹⁵N values in muscle but had slightly different sources of carbon based on δ¹³C measurements in muscle. After removing the influence of age, sex, and blubber thickness, OC concentrations did not vary between ringed seals from the east and west side of the polynya. ΣPCB, ΣDDT, and Σchlordane were found to increase with age for both male and female seals. The inclusion of older (>20 years) female seals, which may have a reduced reproductive effort, may influence the relationships in females. Stable isotopes failed to describe OC concentrations in ringed seals suggesting that diet was not a major factor in variation of OC concentrations within this ringed seal population. Cis- and trans-chlordane, oxychlordane, and heptachlor epoxide were all nonracemic in the ringed seal blubber but did not vary with age, sex, or collection site. α-HCH appeared racemic (enantiomeric fraction = 0.50 ± 0.01) in the seals, although this EF is different than those previously observed in their prey species, and was found to vary significantly with age. EF values in the ringed seals varied considerably from other Arctic marine mammals and seabirds, providing addition evidence that the type(s) and characteristic(s) of the enzymes involved in biotransformation of chiral OCs vary between these organisms. Received: 11 April 2001/Accepted: 27 June 2001     

Place of transmetatarsal amputations: a 5-year experience and review of the literature

A series of 30 patients who underwent transmetatarsal amputation over a 5-year period was analysed. The indications for amputation were gangrene, rest pain and ulceration. The mean age was 75 years and the male to female ratio was 3:2. A higher level of amputation was required in 50% of patients. Of a series of factors analysed for their influence upon outcome (age, diabetes, peripheral pulse status, pre-existing infection, smoking habits, previous digital amputation, prior sympathectomy and/or vascular reconstruction), none had any predictive value in terms of wound healing.     

Computer image sperm selection as a novel approach to subzonal insemination in the human

Utilizing real-time computer image analysis, individual spermatozoawere selected using microaspiration. Selection criteria werebased on potential hyperactivation motility characteristics;the amplitude of lateral head displacement >7.5 µm,curvilinear velocity >70 µm/s and linearity of <30%.For this pilot study, 16 patients (eight in each group) wererecruited. Using subzonal insemination (SUZI), up to five (mean= 4.4 ± 0.3) spermatozoa selected using computer-imagesperm selection (CISS) were microinjected, or up to 15 (mean= 12.8 ± 1.3 SD) unselected spermatozoa. In the groupwhich utilized CISS, 28 out of 49 (57%) oocytes were fertilizedcompared with 13 out of 52 (25%) utilizing conventional SUZI(P < 0.04); polyspermy was 20% (n = 10) and 2% (n = 1) respectively.CISS with SUZI showed increased efficiency in achieving fertilizationand is a novel approach to studying individual sperm functionin a sperm egg bioassay where gamete ratios are close to unity.     

Effects of cigarette smoke dose and time after smoke exposure on uptake of asbestos fibers by rat tracheal epithelial cells

We have previously shown that exposure of excised rat tracheal segments to cigarette smoke followed by exposure to a solution of amosite asbestos increases uptake of asbestos fibers compared to exposure to air followed by asbestos. To learn more about the mechanism of smoke-enhanced fiber uptake, we evaluated the effects of amount of smoke and time delay between smoke exposure and asbestos exposure on fiber penetration into the epithelium. To determine whether amount of smoke exposure affected this process, we exposed tracheal segments to 1, 3, or 6 puffs of smoke and subsequently to 5 mg/ml amosite asbestos for 1 h. The segments were then maintained in organ culture for up to 7 d. Asbestos uptake was evaluated by counting fibers in the epithelium by light microscopy. Exposure to increasing numbers of puffs of smoke produced a dose-related increase in fiber uptake at 1 d, 3 d, and 7 d after exposure. To determine whether asbestos exposure needed to occur immediately after smoke exposure for enhanced uptake of fibers to occur, we exposed tracheal segments to 6 puffs of smoke and then delayed exposure to asbestos for 0 (immediate exposure), 3, 18, or 48 h. Tracheas were again maintained in organ culture for up to 7 d after asbestos exposure. Delayed exposure to asbestos after 6 puffs of smoke produced an increase in fiber uptake, even with an interval as long as 48 h between smoke and asbestos exposure; however, the absolute magnitude of fiber uptake was less than that seen with immediate postsmoke asbestos exposure. If catalase was added to the asbestos solution, the smoke-enhanced uptake was abolished, no matter what the time delay.(ABSTRACT TRUNCATED AT 250 WORDS)     

Spherical lesion phantoms for testing the performance of elastography systems

A set of three cubic one-litre phantoms containing spherical simulated lesions was produced for use in comparing lesion detection performance of different elastography systems. The materials employed are known to be stable in heterogeneous configurations regarding geometry and elastic contrast identical with (storage modulus of lesion material) / (storage modulus of background material), and regarding ultrasound and NMR properties. The materials mimic soft tissues in terms of elastic, ultrasound and NMR properties. Each phantom has only one value of elastic contrast (3.3, 4.6 or 5.5) and contains arrays of 1.6 mm, 2 mm, 3 mm and 4 mm diameter spherical simulated lesions. All the spheres of a given diameter are arranged in a regular array with coplanar centres. Elastograms of an array made with ultrasound allow determination of the depth range over which lesions of that diameter and elastic contrast can be detected. Two phantoms are made from agar-plus-gelatin-based materials, and one is made from oil-in-gelatin dispersions. The methods for producing the phantoms are described in detail. Lesion detection performances for two ultrasound systems, both operating at about 7.5 MHz and focused at about 5 cm, were quantified with distinctions between the two systems demonstrated. Neither system was capable of detecting any of the 1.6 mm lesions. Phantoms such as these should be useful in research labs that are refining hardware and/or software for elastography.