An alternative approach to contrast-detail testing of X-ray image intensifier systems.

The difficulties of making the results of threshold contrast-detail diameter tests on X-ray image intensifier systems consistent with published performance standards are discussed. The current approach to contrast-detail testing is described and an alternative method intended to give greater consistency for all image intensifier input field diameters proposed. The current and alternative test conditions are compared on two image intensifier systems. The results obtained show that the contrast-detail curves for image intensifier systems with a wide range of input field diameters can be effectively normalized to be directly comparable to a common reference standard by applying the proposed alternative test conditions. The implications of this result on the interpretation of the contrast-detail test are discussed.     

Space time clustering of births in SIDS: do perinatal infections play a role?

The aetiology of sudden infant death syndrome (SIDS) remains uncertain; many causal pathways have been proposed. In this paper we have examined firstly the variation in the risk of SIDS with age, month of death and month of birth; and secondly the space time clustering of SIDS deaths, and, separately, space time clustering of their births. Data were obtained from the Office of Populations, Censuses and Surveys on all certified SIDS deaths in the period; children were assigned grid references for the address of birth and of death. Data on number of births were abstracted from published material. A log-linear modelling technique was used to investigate the separate effects of age, month of death and month of birth on the risk of SIDS. The Knox method was used to investigate space time clustering of deaths and of births of children who died of SIDS. Separate, statistically significant effects were found for age, month of death and month of birth. There was minor space time clustering of SIDS births and deaths at large time and space intervals, and a marked space time clustering of births in short space time intervals in the first quarter of the year. The finding of an effect of month of birth on the risk of SIDS, and of space time clustering of births suggest that a perinatal hazard--possibly of infectious origin--may play a role in the aetiology of SIDS.     

Overcoming complications of breast implants.

Having nice breasts is important to many women and their self-images. For those women who have had congenital deformities, were not blessed naturally with the shape they wanted, have had experiences that have adversely affected breast tissue, or have had a mastectomy as a result of breast cancer, breast implants can provide a boost in self-confidence. This article provides an overview of breast implant issues and treatments, and reviews breast implant complications, their potential causes and treatments.     

Increased limb salvage with intraoperative and postoperative ankle level urokinase infusion in acute lower extremity ischemia.

Over a 30-month period (May 1988 to November 1990) 143 acutely ischemic lower extremities (126 patients) were treated with an aggressive surgical approach that included ankle level tibial-peroneal artery thromboembolectomy. Twelve lower extremities in 10 patients that remained ischemic were further treated with adjuvant ankle level urokinase infusion. Sixteen ankle level arteries in 12 extremities were infused with an intraoperative bolus (1 to 2) of urokinase (50,000 to 100,000 units). Continuous postoperative urokinase (25,000 to 50,000 units per catheter per hour x 1 to 5 days) was infused through ankle level arteriotomies in 10 extremities (14 arteries) that did not improve with the initial intraoperative bolus. Concomitant bypass grafting was necessary in four extremities. With adequate inflow established, adjuvant ankle level urokinase salvaged all 12 extremities. The mean increase in ankle/brachial pressure index was 0.84. During continuous postoperative urokinase infusion, lower extremity bleeding requiring blood transfusion occurred in four patients (50%). No deaths occurred in the operative period. Although rhabdomyolysis occurred in 90% of patients, no patients had renal insufficiency. The addition of ankle level urokinase delivery increased the potential limb salvage from 90% of the entire 143 extremities treated during this period to an actual limb salvage of 98%. A mean follow up of 13 months (6 to 36 months) identified one late amputation. Despite the demanding postoperative management required in these patients and the frequent need for early reoperation, the limb salvage obtained justifies this aggressive adjuvant technique in the management of the acutely ischemic lower extremity.     

Differential Contractile Response of Cultured Microvascular Pericytes to Vasoactive Agents

Objective: Microvascular pericytes may contract in two different ways: In the first, a circumferential or radial mechanical force applied at right angles to the long axis of the vessel may constrict the underlying vessel affecting blood flow and transmural pressure. Retraction and elongation of pericyte processes may also occur tangentially and at right angles to the vessel axis and alter microvessel permeability by changing the amount of ablumenal surface covered or the openness of interendothelial junctions. In this study, cultured pericytes were utilized as a model experimental system to determine if vasoactive stimulation changes their shape in a manner consistent with this hypothesis. Methods: Pericytes cultured from isolated rate capillaries were subjected to angiotensin II and histamine. Their response was monitored by measuring the area of nonyielding substrate covered by the pericytes and the manner in which their shape changed. Shape changes were quantified by calculating the surface area: perimeter perimeter ratios. Results: Histamine significantly reduced surface area covered and the surface area: perimeter ratio. The pericyte processes retracted, resulting in elongated, spindle-shaped cells. These effects were nullified by the H₁ blocker diphenhydramine suggesting a receptor-specific response. Angiotensin II also elicited contraction and reduced surface area, but the cells contracted laterally and longitudinally. The surface area: perimeter ratios also decreased. Conclusions: These results indicate that pericytes are capable of two types of contractile responses in culture, depending on the specific vasoactive stimulus.     

Elevated NMDA receptors in parkinsonian striatum.

Dopamine-glutamate interactions contribute to normal striatal function and have been implicated in neurotoxicity at nigrostriatal dopamine (DA) terminals. The present study examined the striata of idiopathic Parkinson's disease (PD) patients and age-matched controls for regional differences in the DA transporter and binding to N-methyl-D-aspartate (NMDA) receptors. [3H]Mazindol labeling of the DA transporter was reduced by 70-80% in the caudate and putamen of PD patients, with reductions being more extensive dorsally than ventrally. In contrast, L-[3H]glutamate binding to NDMA-sensitive receptors was 20-40% higher in PD cases than in controls. These findings raise the possibility that modifications occur within corticostriatal glutamate synapses of PD patients, possibly as a consequence of reduced nigrostriatal DA activity.     

Nosocomial viral infections in a pediatric service: example of rotaviral gastroenteritis and respiratory syncytial viral bronchiolitis]

Nosocomial infections are a preoccupation in a pediatric hospital mainly during the winter with bronchiolitis and gastroenteritis epidemics. We have examined the risk factors of nosocomial infections. MATERIAL AND METHODS: A prospective study was conducted between November, 1999 and March, 2000 in the infants units of the Le Havre hospital. We systematically listed the admissions and contacted the family after their discharge by phone. A geographic information system was implemented to display the epidemiological data; this software is able to illustrate the sectors at risk. RESULTS: During the study, 687 infants were hospitalized of whom 458 for bronchiolitis and community-acquired gastroenteritis. Mean age was 5.4 months old. No nosocomial bronchiolitis occurred. Prevalence of nosocomial gastroenteritis was 10% (68 cases including nine after discharge). Infants with nosocomial infection were younger than those with community-acquired infection (6.6 months vs. 11.2 months, P < 0.01). The mean length of stay was longer in nosocomial infection (7.7 vs. 4.1 days, P < 0.05). Among the infants with bronchiolitis, 16% have developed nosocomial intestinal infections (RR = 2.65, IC: 1.59-4.4; P < 0.01). The geographic analysis pointed the area with nosocomial risk (bedroom without water, nearness of nurse office and games room). CONCLUSION: Geographic information system is a part of the quality control system and may have some interaction effect on final decision making. Incidence of nosocomial infections showed the need for a prevention strategy in a pediatric hospital.