Reductive cleavage of the disulfide bonds of the collagen IV noncollagenous domain in aqueous sodium dodecyl sulfate: absence of intermolecular nondisulfide cross-links

OBJECTIVES: The goal of this study was to develop an accurate, simplified proximal isovelocity surface area (PISA) method for calculating volume flow rate using lower blue-red interface velocity produced by a color Doppler zero baseline shift technique. BACKGROUND: The Doppler color proximal isovelocity surface area method has been shown to be accurate for calculating the volume flow rate (Q) across a narrowed orifice by the formula Q = PISA x Blue-red interface velocity. A hemispheric model is generally used to calculate proximal isovelocity surface area (PISA = 2 pi a2, where a = the radius corresponding to the blue-red interface velocity). Although a hemispheric model is simple, requiring measurement of one radius, it may underestimate the actual volume flow rate because, in the general case, the shape of a proximal isovelocity surface area is hemielliptic. Although a hemielliptic model is generally more accurate for calculating proximal isovelocity surface area, it is more complex, requiring measurement of two orthogonal radii. METHODS: Sixteen in vitro constant flow model studies were performed using planar circular orifices (diameter range 6 to 16 mm). The blue-red interface velocity was changed from 3 to 54 cm/s using color Doppler zero baseline shift. RESULTS: 1) With decreasing blue-red interface velocity, the size of the proximal isovelocity surface area was increased, and its shape changed from hemielliptic to hemispheric. 2) With the blue-red interface velocity in the range 11 to 15 cm/s, the proximal isovelocity surface area became nearly hemispheric; however, it was difficult to determine the blue-red interface radius at a blue-red interface velocity < 10 cm/s because of interface fluctuations. 3) Calculated volume flow rate using the hemispheric proximal isovelocity surface area model with a single radius was relatively accurate at a blue-red interface velocity of 11 to 15 cm/s (mean percent difference from actual volume flow rate was -3.6%). CONCLUSIONS: Because the shape of the proximal isovelocity surface area is nearly hemispheric at a blue-red interface velocity of 11 to 15 cm/s, volume flow rate can be accurately calculated in this proximal isovelocity surface area interface velocity range (produced by zero baseline shift) by measuring a single-interface radius. This approach should be clinically useful for calculating the volume flow rate across stenotic and regurgitant valves and across shunt defects.     

Fetal H-2 odortypes are evident in the urine of pregnant female mice

PURPOSE: Patients with insulin-dependent diabetes mellitus (IDDM) are especially susceptible to microangiopathic complications such as nephropathy, retinopathy, and neuropathy. Microangiopathic changes are also the most important findings in histopathologic studies of the inner ear and central nervous systems in diabetic subjects. No previous studies have measured acoustic-reflex latencies (ARL) or amplitudes (ARA) in patients with IDDM. ARL and ARA reflect the function of the acoustic-reflex arch. Furthermore, possible changes in the tympanic membrane, ossicular chain, and stapedius muscle may affect the shape of acoustic-reflex. SUBJECTS AND METHODS: Acoustic-reflex thresholds, latencies, and amplitudes were studied in 53 patients with IDDM and 42 randomly selected nondiabetic control subjects, aged between 20 and 40 years, using the Madsen Model ZO 73 Impedance Bridge (Madsen Electronics, Copenhagen, Denmark). Subjects with an abnormal tympanic membrane, conductive hearing loss, and known cause for hearing impairment eg, noise damage, were excluded from the study. RESULTS: There were no differences between control and diabetic subjects in the contralateral acoustic-reflex thresholds. In contrast, patients with IDDM had longer ARLs and decreased ARAs compared with those of control subjects. ARA amplitude had linear correlation with the amplitude of tympanogram, whereas ARL had no linear correlation with auditory brainstem latencies in the same study subjects. Acoustic-reflex responses in insulin-dependent diabetic patients were not associated with the duration of diabetes, metabolic control, microangiopathy, or neuropathy. CONCLUSIONS: Prolonged ARLs and decreased ARAs in patients with insulin-dependent diabetes are probably caused more by the stiff middle ear system than disturbances in the brainstem.     

Inhibition of auxin movement from the shoot into the root inhibits lateral root development in Arabidopsis

In roots two distinct polar movements of auxin have been reported that may control different developmental and growth events. To test the hypothesis that auxin derived from the shoot and transported toward the root controls lateral root development, the two polarities of auxin transport were uncoupled in Arabidopsis. Local application of the auxin-transport inhibitor naphthylphthalamic acid (NPA) at the root-shoot junction decreased the number and density of lateral roots and reduced the free indoleacetic acid (IAA) levels in the root and [3H]IAA transport into the root. Application of NPA to the basal half of or at several positions along the root only reduced lateral root density in regions that were in contact with NPA or in regions apical to the site of application. Lateral root development was restored by application of IAA apical to NPA application. Lateral root development in Arabidopsis roots was also inhibited by excision of the shoot or dark growth and this inhibition was reversible by IAA. Together, these results are consistent with auxin transport from the shoot into the root controlling lateral root development.     

Cost-effectiveness analysis of spinal cord stimulation in treatment of failed back surgery syndrome

This article presents an analysis of the medical costs of spinal cord stimulation (SCS) therapy in the treatment of patients with failed back surgery syndrome (FBSS). We compared the medical costs of SCS therapy with an alternative regimen of surgeries and other interventions. Externally powered (external) and fully internalized (internal) SCS systems were considered separately. Clinical management models of each of the therapy alternatives were derived from the clinical literature, retrospective data sets, expert opinion, and published diagnostic and therapy protocols. No value was placed on pain relief or improvements in the quality of life that successful SCS therapy can generate. We found that by reducing the demand for medical care by FBSS patients, SCS therapy can lower medical costs. On average, given current screening and efficacy rates, SCS therapy pays for itself within 5.5 years. For those patients for whom SCS therapy is clinically efficacious, the therapy pays for itself within 2.1 years.     

An improved method for studying microvascular geometry using fluorescent dyes: preventing dye extravasation, preserving dye integrity and enhancing tissue morphometry

Information on notified tuberculosis cases collected by the Algerian Ministry of Health and Social Affairs (Ministère de la Santé et des Affaires Sociales Algérien) from 1982-1990 show that 13,916 cases were notified in 1982 and 10,864 in 1990, of which 67%-71% were cases of pulmonary tuberculosis (TP) and 25-29% cases of extrapulmonary tuberculosis (TEP). New cases of smear-positive TP represented 49-55.4% of all cases and the majority of TP (69-79% depending on the year). These forms particularly affected men aged between 20 and 39 and both men and women over the age of 60. The annual incidence of tuberculosis of all forms fell by 40.3% in 9 years, from 72 cases per 100,000 in 1982 to 43 cases in 1990. Similarly, the annual incidence of smear-positive TP fell from 32 per 100,000 to 22 cases (a decline of 37%), and mainly affected the age group 20-39 years. Lymphadenitis remained the most common TEP (a total of 32% in 1990), the fall in incidence of which was similar to that of TP, although slightly less marked. Whilst a firm diagnosis of new TP cases is provided mainly by direct smear examination, TEP are unfortunately rarely confirmed. The HIV pandemic, which has hardly touched Algeria as yet, does not for the moment play a significant role in tuberculosis morbidity in the community.