Preliminary observations on the neuromuscular abnormalities in patients with organ failure and sepsis

Objective To estimate the incidence and nature of neuromuscular abnormalities in a representative group of ITU patients.Design Prospective sequential study.Setting Teaching hospital ITU.Patients 23 patients who eventually stayed >7 days on ITU who had no contraindication to muscle biopsy and whose relatives gave informed consent.Measurements and results Muscle histopathology, neurophysiological studies, record of all drugs administered, APACHE II score, organ system failure score, presence or absence of sepsis, clinical evaluation of neuromuscular problems, time to hospital discharge. Heterogeneous neuromuscular abnormalities were present in 22 out of 23 patients studied and included axonal neuropathy, denervation, generalised fibre atrophy, non-specific myopathy and necrotising myopathy.Conclusion Neuromuscular abnormalities are almost invariable in longstay intensive care patients and the resulting weakness may seriously delay hospital discharge. Various abnormalities were seen but no obvious aetiological factors were identified. The origin of the abnormalities is probably multifactorial.This study was carried out with financial assistance from the Joint Research Board of St. Bartholomew's Hospital, the Locally Organised Research Scheme of North East Thames Regional Health Authority, and the excellent technical assistance of Miss Fiona Withey and Miss Joanna Wood.     

Components of the melatonin message in the response to photoperiod of the tammar wallaby (Macropus eugenii)

Female tammars experiencing long-day photoperiod (LD 15:9) are in a reproductive state termed seasonal quiescence. After a change to LD 12:12, a sequence of endocrine events, dependent on a melatonin message being interpreted during the next 3 days, leads to the disappearance of a morning pulse of prolactin on day 4, and to reactivation of the quiescent corpus luteum by day 8. Elements of the message were investigated in three experiments. In experiment 1, tammars on LD 15:9 were injected with melatonin 2.5 hr before lights out on 0-5 successive days. All those receiving four or five daily injections, and six of ten receiving two or three injections, reactivated. In experiment 2, tammars on LD 15:9 were injected with melatonin or oil on 5 consecutive days to achieve a lengthening of the period of elevated melatonin from 9.0 hr to 9.5 hr, 10 hr, 10.5 hr, and 11.5 hr respectively. One of five tammars experiencing 10 hr and seven of ten experiencing the longer periods reactivated. In experiment 3, tammars on LD18:6 received melatonin 6 hr, 6 + 3 hr or 3 hr before lights out for ten successive days. Between injections the melatonin concentrations returned to basal levels. The treatments thus provided a skeletal increase in the profile of melatonin from 6 to 9 hr or 6 to 12 hr. All those treated at 6 + 3 hr reactivated and three of five treated at 6 hr only reactivated. We conclude that the tammar stores information about the change in the maximum duration of elevated melatonin experienced each night and, after three successive periods in which the duration is greater than 10.5 hr, it reactivates. Since reactivation cannot occur until completion of the third dark phase, the processing center must be active during the fourth day, prior to the abolition of the prolactin peak.     

Sera from simian immunodeficiency virus-infected rhesus macaques inhibit lymphocyte proliferation.

Rhesus macaque monkeys infected with the simian immunodeficiency virus (SIV) develop a syndrome mimicking acquired immunodeficiency syndrome (AIDS) in humans. We had demonstrated previously that sera from individuals infected with human immunodeficiency virus (HIV) inhibit the proliferation of lymphocytes from healthy noninfected subjects and that this phenomenon was associated with the development of clinical AIDS. Thus, we sought to determine whether sera from SIV-infected monkeys would also inhibit lymphocytes from healthy humans and SIV-negative rhesus monkeys. Sera from SIV-infected monkeys were compared with sera from uninfected animals and cultured with cells from healthy human volunteers or SIV-negative monkeys in the presence or absence of phytohemagglutinin (PHA). Cell proliferation was determined by measuring the incorporation of radiolabeled thymidine into cellular DNA. Sera from SIV-infected monkeys suppressed the proliferation of human and non-human primate lymphocytes. This activity appears to be similar to that described for sera from HIV-1-infected humans. Therefore, rhesus macaques infected with SIV provide a model for the study of serum inhibitory factors previously reported in AIDS patients.     

Haemophilus organisms: Urinary tract pathogens in children?

The incidence and significance of isolation of Haemophilus species from urine specimens was determined at a pediatric referral center. The incidence was 0.27%, and half the isolates were pathogens. Evaluation of incidence and a cost analysis led to the conclusion that routine efforts to isolate Haemophilus from urine are not cost-effective.