Microstructural effects on the stress corrosion cracking behavior of medium and high strength steels

The effects of variations in microstructure and strength level on the stress corrosion cracking susceptibility of three medium to high strength steels, H13, 300M, and HY-130, in 3.5 pct NaCl have been systematically studied. Superimposed on the expected inverse dependence of K_ISCC on yield strength was more than an order of magnitude reduction in crack growth rate, with no strength penalty. These results have been analyzed in terms of the possible relative roles of different microstructural features, in particular retained austenite, whose detailed behavior is the subject of a companion paper.     

Bauhinia purpurea and Pisum sativum lectin binding in human breast

The binding of biotinylated bauhinia purpurea (BPA) and pisum Sativum (PSA) lectins to paraffin-embedded tissue sections from 10 normal breast and 55 breast carcinoma has been investigated by applying avidin biotin peroxidase method (ABC). BPA showed very low affinity for normal breast epithelium and the binding was confined to the luminal surface. Eighty-seven percent carcinoma bound BPA, and the staining patterns varied depending on the histologic grade of tumors: luminal surface binding in grade 1 carcinomas; diffuse, granular cytoplasmic with para- or perinuclear deposits and staining along the plasma membrane in grade 2 and grade 3 carcinomas. PSA bound consistently to the luminal surface of all ducts and acinar cells of normal breast tissue. PSA was reactive with all carcinoma but the staining profiles were similar regardless of the tumor differentiation. It is concluded that the lectins used in this study have limited usefulness in routine diagnosis.     

Streptococcal preseptal cellulitis complicated by the toxic Streptococcus syndrome

BACKGROUND: After decades of decline in the incidence of severe infections secondary to group A streptococci, a dramatic increase in the frequency and severity of infections with these organisms has been reported since 1984, including a "toxic Streptococcus syndrome," resembling staphylococcal toxic shock syndrome. To the authors' knowledge, this entity has never been described after ocular infection. METHODS: In a previously healthy 3-year-old boy, preseptal cellulitis developed secondary to minor trauma to the eyelid, progressing rapidly to hypotension, respiratory distress, and an erythrodermic desquamating rash. Ocular and blood cultures grew group A beta-hemolytic streptococci. Appropriate antibiotic coverage and management of systemic manifestations led to rapid improvement, although necrosis developed in the right upper anterior eyelid, requiring skin grafts. RESULTS: More than 3 years since the incident, the patient is free of infection and has a good cosmetic result after skin grafting and revisions for scarring and adhesions. CONCLUSIONS: Streptococcal preseptal cellulitis is not unusual, particularly after trauma. Ophthalmologists must be aware of the re-emergence of more virulent organisms with increased potential for morbidity and mortality.     

Interleukin-1 beta facilitates afferent sensory transmission in the primary somatosensory cortex of anesthetized rats

The effect of topical application of human recombinant interleukin-1 beta (IL-1) on afferent sensory transmission to the neurones in the primary somatosensory (SI) cortex was determined in anesthetized rats. Quantitative determination of the effect of IL-1 was made by generating post-stimulus time histograms of unit responses to the stimulation of receptive field. IL-1 (0.01, 0.1, 1.0 U) significantly facilitated afferent sensory transmission in SI cortical neurones (n = 22). IL-1-induced facilitation fully recovered by 60 min after drug. In control experiments (n = 10), saline solution containing 0.2 bovine serum albumin, used as a vehicle, did not affect afferent sensory transmission. Our results suggest that IL-1 may be involved in the processing of afferent sensory information in the SI cortex of rats.     

Progressive effect of endurance training on VO2 kinetics at the onset of submaximal exercise

The rates of increase in O2 uptake (VO2) after step changes in work rate from 25 W to 60% of pretraining peak VO2 (VO2 peak) were measured at various times during an endurance training program (2 h/day at 60% pretraining VO2 peak). Seven untrained males [23 +/- 1 (SE) yr] performed a series of repeated step changes in work rate before training (PRE) and after 4 days (4D), 9 days (9D), and 30 days (30D) of training. VO2 kinetic responses were determined from breath-by-breath data averaged across four repetitions and analyzed using a two-component exponential model. Mean response time (time taken to reach 63% of steady-state VO2) was faster (P < 0.01) than PRE (38.1 +/- 2.6 s) at both 4D (34.9 +/- 2.4 s) and 9D (32.5 +/- 1.8 s) and was faster (P < 0.01) at 30D than at all other times (28.3 +/- 1.0 s). Blood lactate concentrations (after 6 min of cycling) were also lower at 4D and 9D than PRE (P < 0.01) and were lower at 30D than at all other times (P < 0.01). VO2 peak was unchanged from PRE (3.52 +/- 0.20 l/min) at 8D (3.55 +/- 0.20 l/min) but was increased (P < 0.01) at 30D (3.89 +/- 0.18 l/min). Muscle oxidative capacity (maximal citrate synthase activity) was not significantly increased until 30D (P < 0.01). It is concluded that at least part of the acceleration of whole body VO2 kinetics with endurance training is a rapid phenomenon, occurring before changes in VO2 peak and/or muscle oxidative potential.     

Infant weaning practises of some Idoma women in Makurdi, Nigeria

The weaning practices in infants aged 4-9 months of two hundred Idoma women resident in Makurdi were examined. A pre-tested standard questionnaire was used to collect data from mothers who regularly visited the post-natal health clinics in Makurdi. The results showed that better educated mothers breast fed for a shorter time or planned to cease breast feeding after a shorter period than mothers who had little education or no formal training. Most mothers (97%) fed milk formula which they claimed was used to supplement breast milk and was good for their babies. The most influential factors were the hospital and the husband. The majority of the mothers fed pap; 73% using corn in its preparation, with 91% of them storing such paps in flask. More than half of the mothers used a bottle in feeding the paper or gruel to their infants while a similar proportion (65.5%) fed legumes to their infants in addition to fruits. The implications of these practices in comparison with other ethnic groups is discussed.     

Determination of cognitive hemispheric dominance by "stereo" transcranial Doppler sonography

BACKGROUND AND PURPOSE: Transcranial Doppler sonography (TCD) can assess blood flow velocity changes induced by focal brain activation. Therefore, TCD may have the potential to identify hemispheric dominance for cognitive tasks. METHODS: Using a system with two TCD probes ("stereo" TCD), we monitored simultaneously both middle cerebral arteries (MCAs) of 14 healthy right-handed volunteers while they performed cognitive tasks. The averaged blood flow velocity ratio of the two MCAs and the hemispheric blood flow velocity shift induced by the cognitive task were calculated. RESULTS: In every subject, language tasks resulted in blood flow velocity shift to the left compared with visuospatial tasks. Mean MCA blood flow velocity shift to the left was 1.67%, 2.01%, and 2.31% in three language tasks. Mean blood flow velocity shift to the right was 1.67% and 2.31% in two visuospatial tasks. CONCLUSIONS: Bilateral simultaneous MCA blood flow velocity monitoring and averaging during cognitive tasks can help to identify hemispheric dominance for cognitive tasks in individuals.     

Large arachnoid cysts at the cranial base

Two infants who presented with macrocephaly had very large noncommunicating cysts at the cranial base that were displacing the brain. Only one of the patients was hydrocephalic; he eventually underwent ventriculoperitoneal shunting after craniotomy and attempted internal drainage of the cyst. The other infant had a cystoperitoneal shunt. Both have done well after 4 and 6 years of follow-up, respectively. These large arachnoid cysts are bilateral lesions with the potential for severe surgical complications and a questionable possibility of cure. The authors recommend systematic radiological investigation to decide the appropriate therapy, including an analysis of the patency of the subarachnoid pathways with radionuclide cisternography and cystography. Simple cystoperitoneal shunting may be the appropriate therapy for most of these large lesions. (Neurosurgery, 6: 76--81, 1980).