Staff carriage of epidemic methicillin-resistant Staphylococcus aureus

Twenty-six nurses were repeatedly screened for carriage of epidemic methicillin-resistant Staphylococcus aureus (EMRSA) immediately before and after duty periods in which they solely attended six patients widely colonized with two EMRSA strains distinguishable by plasmid analysis. EMRSA carriage was detected in 13 nurses. Three EMRSA carriage patterns emerged: transient carriage in 12 nurses, when the EMRSA was isolated from noses or fingers of nurses after duty but was gone before their next day's duty; short-term nasal carriage, seen on occasion in 4 of these 12 nurses, when EMRSA carriage was detected on two consecutive screens; and persistent nasal carriage, seen in 1 nurse only, when the EMRSA was seen on more than two consecutive occasions. All but one of these incidents of carriage could be explained by close patient, rather than environmental, exposure and occurred despite an intensive control programme. Transient or short-term carriage in nurses probably resulted in transfer of the EMRSA between patients. Staff decontamination should be considered following a period of cohort nursing of EMRSA patients, especially if staff members are shortly to nurse unaffected patients. Our findings may explain some of the difficulties in controlling EMRSA.

Chronic voluntary nicotine drinking enhances nicotine palatability in rats

The response of rats to nicotine solutions was examined with the brief-exposure, taste reactivity test and a two-bottle, 24-hr preference test. In Experiment 1, naive nondeprived rats were administered intraoral infusions (0.8 ml infused during 1 min) of distilled water and 1 microgram/ml, 5 micrograms/ml, 10 micrograms/ml, 25 micrograms/ml, 50 micrograms/ml, and 100 micrograms/ml nicotine. The oral motor, taste reactivity (TR) responses of the rats were recorded during the infusion. Nicotine solutions up to a concentration of 50 micrograms/ml elicited a number of ingestive TR responses similar to that by water. Ingestive responses significantly decreased and aversive TR responses significantly increased in response to 100 micrograms/ml nicotine. On the basis of these results, two-bottle preferences for water versus 1 microgram/ml, 5 micrograms/ml, and 0 microgram/ml (water control group) nicotine were measured in three groups of naive rats. Rats initially showed an equal preference for 0 microgram/ml and 1 microgram/ml nicotine. After 16 days of exposure, however, rats developed a significant preference for 1 microgram/ml nicotine. The preference ratio for 5 micrograms/ml nicotine significantly increased during the experiment, but the preference ratio remained significantly less than that for 1 microgram/ml and 0 microgram/ml nicotine solutions. Last, TR responses elicited by intraoral infusions of 1 microgram/ml and 5 micrograms/ml nicotine were then measured in these rats having had the two-bottle experience. Rats showing a two-bottle preference for the 1 microgram/ml nicotine solution displayed significantly more ingestive TR responses to 1 microgram/ml and 5 micrograms/ml nicotine than did the control rats.(ABSTRACT TRUNCATED AT 250 WORDS)

The role of selenium deficiency in occidental dilated cardiomyopathy

The whole blood selenium concentrations were measured in 14 consecutive cases of catheter-proven dilated cardiomyopathy. The mean range of selenium was 59 ng/mL (SD 14). Patients with coronary heart disease had a mean value of 44 ng/mL (9.7) and normal controls had 78 ng/mL (20.1). These results would not support the hypothesis that selenium deficiency is an important causative agent in dilated cardiomyopathy in New Zealand.

Hepatitis B infections after gynaecological surgery

When acute hepatitis B developed in 3 patients who had had gynaecological surgery, the surgeon was found to be a carrier of hepatitis B e antigen. Of 268 patients operated on by this surgeon in one hospital, 247 were screened for markers of recent or current hepatitis B. 22 (9%) had such markers, associated with symptoms in 5. The operations carrying greatest risk of infection were hysterectomy (10/42) and caesarean section (10/51). These findings strengthen the case for vaccination of all surgeons and medical students against hepatitis B.

Chronic voluntary nicotine drinking enhances nicotine palatability in rats

The response of rats to nicotine solutions was examined with the brief-exposure, taste reactivity test and a two-bottle, 24-hr preference test. In Experiment 1, naive nondeprived rats were administered intraoral infusions (0.8 ml infused during 1 min) of distilled water and 1 microgram/ml, 5 micrograms/ml, 10 micrograms/ml, 25 micrograms/ml, 50 micrograms/ml, and 100 micrograms/ml nicotine. The oral motor, taste reactivity (TR) responses of the rats were recorded during the infusion. Nicotine solutions up to a concentration of 50 micrograms/ml elicited a number of ingestive TR responses similar to that by water. Ingestive responses significantly decreased and aversive TR responses significantly increased in response to 100 micrograms/ml nicotine. On the basis of these results, two-bottle preferences for water versus 1 microgram/ml, 5 micrograms/ml, and 0 microgram/ml (water control group) nicotine were measured in three groups of naive rats. Rats initially showed an equal preference for 0 microgram/ml and 1 microgram/ml nicotine. After 16 days of exposure, however, rats developed a significant preference for 1 microgram/ml nicotine. The preference ratio for 5 micrograms/ml nicotine significantly increased during the experiment, but the preference ratio remained significantly less than that for 1 microgram/ml and 0 microgram/ml nicotine solutions. Last, TR responses elicited by intraoral infusions of 1 microgram/ml and 5 micrograms/ml nicotine were then measured in these rats having had the two-bottle experience. Rats showing a two-bottle preference for the 1 microgram/ml nicotine solution displayed significantly more ingestive TR responses to 1 microgram/ml and 5 micrograms/ml nicotine than did the control rats.(ABSTRACT TRUNCATED AT 250 WORDS)

'Cialit' as a tissue preservative: a microbiological assessment

We describe bacterial contamination of a 'Cialit'-preserved cartilage bank which continued after a variety of changes to the harvesting and preservation protocols during a 3-year prospective study. Our results emphasize the importance of adequate tissue bank microbiological screening. Alternative methods of tissue preservation should be considered.

Ultrasound exposure time in routine obstetric scanning

The duration of exposure to ultrasound was measured in 1274 patients having a routine examination during their first visit to an antenatal clinic. The measured median exposure time was 105 s. Since pulsed ultrasound was used (duty cycle of 1 in 800) the actual median maternal exposure time was 131 ms. Exposure of the fetus would usually be less since it rarely occupies the full width of the image. The relevance of exposure time to the safety of diagnostic ultrasound and the implications for users and manufacturers are discussed.

Hemodynamic effects of intermittent transdermal nitroglycerin in chronic congestive heart failure

The hemodynamic effects of intermittent and continuous treatment with transdermal nitroglycerin, 10 mg/24 hours, were compared in 10 patients with chronic congestive heart failure (CHF). Eight patients responded to initial application with more than a 20% reduction in mean pulmonary artery wedge pressure. Cardiac index increased from a control value of 2.1 +/- 0.5 to 2.4 +/- 0.6 liters/min/m2 at 2 hours (p less than 0.05) and mean pulmonary wedge pressure was reduced from 22 +/- 5 to 16 +/- 6 mm Hg (p less than 0.01). The 2 nonresponders had the largest left ventricular volumes on 2-dimensional echocardiograms. Responders were randomized to intermittent (16 hours/day) or continuous (24 hours/day) treatment for 1 month followed by a month of the alternate treatment. After 1 month of intermittent treatment, the hemodynamic response after reapplication was similar to the initial response. After another month of continuous treatment, hemodynamic values 24 hours after application were similar to initial control values and there was no change after removal and reapplication. Thus, the moderate vasodilator effect of transdermal nitroglycerin in CHF is maintained with intermittent treatment, whereas tolerance develops with continuous treatment.

Stages in the structural differentiation of retinal ganglion cells

Using a cultured wholemount technique we have studied the morphological differentiation of ganglion cells in the retina of the rat and cat, during normal development. In both species the differentiation of ganglion cells begins in embryonic life, before embryonic day (E) 17 in the rat and E36 in the cat. It is useful to describe the morphological differentiation of ganglion cells as occurring in three stages. In the first stage, each germinal cell becoming a ganglion cell extends an axon into the fibre layer of the retina and towards the optic disc, and the soma of the cell moves towards the ganglion cell layer. As the soma approaches the ganglion cell layer, the processes that attach its poles to the inner and outer surfaces of the retina are withdrawn. When the soma reaches the ganglion cell layer, a stage of active dendritic growth begins, which lasts until shortly before birth in the cat and until several days after birth in the rat. The cell extends stem dendrites that branch profusely and are commonly tipped by growth cones. The major morphological classes of ganglion cell become distinct in the latter part of stage 2, as do the centroperipheral gradients in ganglion cell size apparent in the cat. During the third stage, the dendritic trees of ganglion cells no longer branch or extend by means of active growth cones. Very considerable growth of all parameters of the cell (soma size, dendrite calibre and length, axon calibre) occurs nevertheless, presumably by interstitial addition of membrane throughout the cell.

An outbreak of Serratia marcescens transmitted by contaminated breast pumps in a special care baby unit

Laboratory surveillance of clinical isolates for Serratia spp. revealed a sudden increase from babies in the Special Care Baby Unit (SCBU). It was established that breast-milk pumps on the post-natal wards were being disinfected inadequately, resulting in contamination of milk and cross-infection within the SCBU. Thirty babies were colonized and no deaths were attributable to the organism. Rectal carriage by the babies was common and often prolonged. The outbreak was brought under control when the method of disinfection of the pumps was changed from soaking in hypochlorite solution to washing at 80 degrees C.

Patients with suspected Lassa fever in London during 1984: problems in their management at St Thomas's Hospital

During 1984, 23 patients in whom a diagnosis of viral haemorrhagic fever was considered presented to the accident and emergency department at St Thomas's Hospital. There were no confirmed cases of viral haemorrhagic fever. Nine patients were transferred to Coppett's Wood Hospital, the nearest specially designated high security isolation unit. Malaria was the final diagnosis in 14, and in six this diagnosis was confirmed only after examining repeated smears at Coppett's Wood Hospital. Transferral of patients to such units is time consuming, expensive, and often unnecessary. Specially designated isolation units in district general hospitals and all teaching hospitals would simplify and improve the care not only of patients with a possible viral haemorrhagic fever but also patients with tuberculosis, multiply resistant staphylococcal infections, and viral infections that may be hazardous if transmitted to immunocompromised patients.

Study of cardiothoracic wound infection at St. Thomas' Hospital

Wound infection occurred after 14.3 per cent of 433 open heart operations. In 309, saphenous veins were harvested for coronary artery bypass grafting (CABG) and 8.7 per cent of sternal wounds and 12.9 per cent of leg wounds were infected. Only 1.6 per cent of the remaining 124 patients who had open heart operations without leg surgery suffered sternal wound infections. In the CABG group sternal infection was theatre-related and significantly associated with length of pre-operative stay, diabetes and re-operation. Similar organisms were isolated from both leg and sternal wounds which suggest that organisms were transferred from legs to sternum with the veins. No clinically relevant cross infection was demonstrated. Skin disinfection and surgical technique seem more important than antibiotic prophylaxis in the control of these infections.

Increase in cervical extensibility during labor induced after isolation of the cervix from the uterus in pregnant ewes

Surgical transection of the cervix was done on eight ewes in late pregnancy. This procedure resulted in most of the length of the cervix being mechanically disconnected from the uterus. Labor was induced by injection of dexamethasone phosphate into a fetal hind limb during operation in four of the eight ewes. The success of the induction of labor was confirmed by observation of increased uterine activity and by measurement of the concentrations of progesterone and 17 beta-estradiol in peripheral plasma. Ewes were put to death approximately 48 hours after injection of dexamethasone and the extensibility of the isolated portion of the cervix was determined. Cervices taken from ewes in which labor had been induced were found to have softened considerably compared to control cervices taken from ewes in which the cervix had been transected without induction of labor. The results suggest that cervical softening can still occur during labor in the absence of any direct mechanical or local vascular connection between the cervix and uterus.

A case of Lassa fever: experience at St Thomas's Hospital

An 18-year-old Nigerian girl, normally resident in Jos, was admitted to hospital for five days before she was diagnosed as having Lassa fever. There were several atypical features in the early stages of here illness, notably the absence of prostration, pharyngitis, or bradycardia and the development of appreciable leucocytosis. Consequent control and surveillance measures required checks for 21 days on 173 people who had had contact with as first line if they had handled her or specimens without taking precautions to avoid direct skin contact with her excretions, secretions, and blood; other contacts were categorised as second line. During her time in hospital she was managed in a single room on a general ward. She visited a number of investigative departments within the hospital, and her specimens were examined in five clinical laboratories. Despite this no secondary cases occurred among either first- or second-line contacts, and there was no serological evidence of subclinical infection among any of the contacts tested (159 people).

Spiral ganglion neuron loss following organ of Corti loss: a quantitative study

The packing density of spiral ganglion neurons was measured in 2.5- and 13-15-month-old guinea pigs, in guinea pigs at various times after drug-deafening or acoustic trauma, and in Waltzing guinea pigs of various ages. Analysis of variance and Duncan's new multiple range tests were used to determine significant differences between treatment/survival groups. Spiral ganglion neurons in young and old normal ears did not have significantly different packing densities. Drug-deaf guinea pigs showed a significant loss of neurons by 2 weeks following treatment, a further significant loss by 2 months, and a marginally significant loss between 4 and 8 months. The neuronal population was then stable through 15 months, at about 13% of normal. Acoustic trauma ears showed the first significant loss isn the lower second turn at 1 month. Long-term (12-14 months post-exposure) trauma ears were highly variable. Waltzers lost about 50% of their normal neuronal population between 4 and 8 months; they showed an unexpected greater-than-normal density at 2 months, possible explanations of which are discussed. Thus, loss of the organ of Corti from various causes results in a slow but progressive loss of spiral ganglion neurons, the time course of which varies with the type of cochlear insult.

Mouse brainstem auditory nuclei development

The cross-sectional areas of brainstem auditory neurons were measured in a potential developmental series of mice. There is no demonstrable neuronal growth between days 1 and 3. Between days 3 and 12 the neuronal somas grow rapidly to their adult size. Most of this growth occurs prior to any cochlear physiological activity and all of it occurs before cochlear maturation. Most brainstem auditory neurons of 45-day-old mice postnatally deprived of sound or with conductive losses are of a size comparable to normal nine-day-old mice.

Effects of neonatal conductive hearing loss on brain stem auditory nuclei

Both postnatal auditory deprivation and experimentally produced conductive hearing losses in mice result in incomplete maturation of most brain stem auditory neurons. The affected groups are: octopus cell, globular cell, small spherical cell, and large spherical cell groups in ventral cochlear nuclei; and the lateral superior olive and medial nucleus of the trapezoid body of the superior olivary complex. When 45 days of auditory deprivation are followed by 45 days of normal acoustic stimulation, there is incomplete maturation of neurons in: multipolar cell, globular cell, small spherical cell, and large spherical cell groups in ventral cochlear nuclei; lateral superior olive and medial nucleus of trapezoid body in superior olivary complex; and central nucleus of inferior colliculus. A critical period exists when adequate sound stimulation is needed for full development of these neurons.

Cochlear nerve projections following organ of corti destruction

Experimental organ of Corti destruction results in (1) secondary loss of all type I spiral ganglion neurons, (2) development of type III spiral ganglion neurons, (3) degeneration of most cochlear nerve myelinated fibers, and (4) terminal degeneration in the ventral and dorsal cochlear nuclei. The first signs of degenerative changes occur by eight days after organ of Corti destruction and degeneration debris remains until 28 weeks after destruction.

Gentamicin-resistant Klebsiella aerogenes in a urological ward

A gentamicin-resistant strain of Klebsiella aerogenes was isolated from the urine of 17 patients out of 237 admitted to a male urological ward between Jan. 21 and May 9, 1977. The factors most frequently associated with K. aerogenes in the urine were catheterisation and antibiotic therapy. Often the epidemic strain (type K16) was found not only in the patients' faeces but also on more remote skin sites such as hands, knees, groins, and the umbilicus. Resistance to gentamicin and many other antibiotics was R-factor mediated. Barrier nursing of colonised patients, stringent staff handwashing with chlorhexidine, and the use of disposable aprons seemed to contain the outbreak. Hand carriage was demonstrated in one nurse 62 days after she had left the ward.