To develop chelating molecules that provide 99mTc-labeled polypeptides of high in vivo stability and high specific activities under mild reaction conditions, an asymmetrical bis(benzohydroxamamide) compound with an amine group, 4'-aminomethyl-N,N'-trimethylenedibenzohydroxamamide [NH2-C3(BHam)2], was designed and synthesized. The amine residue of NH2-C3(BHam)2 was converted to a maleimide group by reaction with N-succinimidyl-6-maleimidohexanoate, and the conjugation product was coupled to thiol groups of a monoclonal antibody against osteogenic sarcoma (OST7, IgG1) pretreated with 2-iminothiolane to prepare C3(BHam)2-OST7. 99mTc radiolabeling of C3(BHam)2-OST7 was performed by the exchange reaction with [99mTc]glucoheptonate. [99mTc]C3(BHam)2-OST7 was further characterized using directly radioiodinated OST7 ([125I]OST7) and [111In]labeled OST7 with 1-[4-[(5-maleimidopentyl)amidobenzyl]ethylenediamine-N,N, N'N'-tetraacetic acid (EMCS-Bz-EDTA) as references. [99mTc]C3(BHam)2-OST7 was obtained with radiochemical yields of over 94% at protein concentrations as low as 0.2 mg/mL at room temperature for 1 h. [99mTc]C3(BHam)2-OST7 remained stable after incubation in freshly prepared murine plasma and in the presence of cysteine. Similar binding affinities to tumor cells were observed between [99mTc]C3(BHam)2-OST7 and [125I]OST7. When injected into normal mice, [99mTc]C3(BHam)2-OST7 exhibited radioactivity levels in the blood similar to [111In]-EMCS-Bz-EDTA-OST7 up to 24 h postinjection with significantly faster elimination rate of the radioactivity from the liver. In nude mice bearing osteogenic sarcoma, no significant differences were observed in the radioactivity levels in the blood and the tumor between [99mTc]C3(BHam)2-OST7 and [125I]OST7 at 24 h postinjection. These findings indicated that C3(BHam)2 provided 99mTc chelate of high stability at low concentrations even when conjugated to an intact antibody. Such characteristics render bis(hydroxamamide) compounds useful as chelating molecules for preparation of 99mTc-labeled polypeptides.

Amides↗

PubMedDate not supplied

Definition of new alleles of MIC-A using sequencing-based typing.

We have sequenced exons 2, 3 and 4 of MIC-A in 23 homozygous cell lines, 22 families and 54 unrelated individuals. This has led to the definition of seven polymorphic positions in exon 2, 13 in exon 3 and 12 in exon 4, yielding a total of 33 different MIC-A allelic specificities, of which 16 have not been described before. The newly defined sequences and those of the alleles defined before were entered into a database of the SCORE program (Helmberg et al., 1998, Tissue Antigens, 51, 587) for comprehensive genotyping analysis. In the tested sample, only one genotype present in two individuals gave rise to an ambiguous genotype. If all possible combinations of the 33 alleles are considered, 10 of 636 combinations are ambiguous. The MIC-A exon 2, 3 and 4 polymorphism is characterized by diallelic single base exchanges and by a considerable degree of exon shuffling. The majority of heterozygote positions identified are non-synonymous, i.e. five of seven in exon 2, 13 of 13 in exon 3 and eight of 12 in exon 4, suggesting an important function for the MIC-A polymorphism.

Adult↗

PubMedDate not supplied

Interpenetrating polymer networks of alginate and polyethylene glycol for encapsulation of islets of Langerhans.

A mixture of alginate and polyethylene glycol acrylate was investigated as a system for the encapsulation of islets of Langerhans. This system showed dual crosslinkability: the alginate was ionically crosslinked by multivalent cations, and the PEG was covalently crosslinked by photoactivated free radical polymerization. The major advantage of the dually crosslinkable system was the chemical stability of the resultant gels due to the presence of covalent bonds that maintain the integrity of the gel as opposed to reversible ionic linkages that were the only mode of crosslinkage in previous generations of alginate-based encapsulation systems. The physical aspects of gelation of such alginate/PEG compositions were investigated. Diffusion of dextrans of known molecular weights through these gels was studied in order to shed light on the hydrogel porosity and permeability. In vitro viability and function tests demonstrated that these gels were biocompatible. Islets encapsulated in these systems were healthy and retained both viability and insulin secretory function.

Alginates↗

PubMedDate not supplied

Validation of rat endometriosis model by using raloxifene as a positive control for the evaluation of novel SERM compounds.

Approximately 10% of women of reproductive age suffer from endometriosis, a potentially painful disease process and important cause of female infertility. Raloxifene, a commercially available SERM (selective estrogen receptor modulator) compound, used for the treatment of postmenopausal osteoporosis, has preclinically demonstrated its estrogen antagonist effect on uterine tissue in rats. There is potential that SERM compounds may become a viable treatment option for human endometriosis, although more investigation is needed. In this study, raloxifene was administered at various doses to determine the efficacy and an appropriate dose level for use as a positive control in a rat model of endometriosis. Prior to dose administration, all rats underwent a bilateral ovariectomy, autologous transplantation of uterine tissue onto the peritoneal surface of the abdominal wall, and implantation of a subcutaneous estrogen pellet (E2). Two separate postsurgical experiments were performed. In experiment 1, following a 4-wk recovery, the rats bearing implants were assigned to three groups: (1) removal of the E2 pellet and dosing vehicle only (n = 7); (2) E2 and vehicle (n = 6); and (3) E2 and raloxifene at 10.0 mg/kg (n = 6). In experiment 2, also following a 4-week recovery, the rats bearing implants were assigned to five groups (n = 8/group): (1) E2 and vehicle only; (2) E2 and raloxifene, 0.3 mg/kg/d; (3) E2 and raloxifene, 1.0 mg/kg/d; (4) E2 and raloxifene, 3.0 mg/kg/d; (5) E2 and raloxifene, 10.0 mg/kg/d. All rats were dosed orally BID for 14 d. At the end of the study, the implanted endometrium was remeasured and compared to the pretreatment measurement. The results from both studies demonstrated that Raloxifene at only one dose (10.0 mg/kg) displayed significant implant regression (p < .05). Subsequently, our rat endometriosis experimental model consistently uses the exogenous E2 pellet and raloxifene at 10 mg/kg, BID, as a positive control to help screen and compare novel SERM compounds.

Animals↗

PubMedDate not supplied

Risk factors for work-related low back pain in the People's Republic of China.

A critical review was conducted of studies of work-related low back pain in the People's Republic of China. The published literature in both the English and Chinese languages from 1983 to 1997 was reviewed for studies that permitted the calculation of prevalence ratios. Thirty-five papers were identified initially, and after quality inclusion/exclusion criteria were applied, 16 (14 in Chinese and two in English) were selected for more detailed review. Prevalence ratios were statistically elevated in all but two of the selected studies. Prevalence ratios for individual groups ranged from 2.0 to 8.5 for bending and twisting, 1.5 to 14.3 for static posture, 1.9 to 5.5 for whole-body vibration, and 2.6 to 9.4 for low-temperature exposure. The literature was limited by the absence of standardized and robust measures of low-back-pain outcomes and exposures and by the omission of fundamental details from research reports. Even with these limitations, the review findings suggest that three physical risk factors, all well known in the international literature, are associated with the prevalence of low back pain in the People's Republic of China.

China↗

PubMedDate not supplied

Exposure limits for ultra-short wave radiation in work environments.

Exposure limit values for ultra-short wave radiation of humans were derived on the basis of epidemiological survey and experimental exposure of rabbits. Eighteen male rabbits were divided into 4 groups randomly. Three groups were irradiated with ultra-short waves (100 MHz) at 35, 1.5-3.5, and 0.07 mW/cm2 power density in an E-polarized TEM Cell at 24 +/- 4 degrees C ambient temperature. The last group in a sham chamber served as controls. Irradiation was performed 3 hours per day, 5 days per week for 24 weeks. Thermal effects occurred in the group irradiated at 35 mW/cm2. The thermal threshold limit value was set at 1.5 mW/cm2. An epidemiological survey was carried out on 136 factory workers and TV operators exposed over one year to ultra-short wave radiation at 0.2 mW/cm2. They were compared with 108 controls. The only complaint of the exposed group was neurosis. The exposure limit value (ELV) to short wave radiation was set at 0.2 mW/cm2 by using a 15- and 20-fold safety factor.

Animals↗

PubMedDate not supplied

Muscular asthenopia and eccentric ablation after photorefractive keratectomy.

PURPOSE: To investigate the relationship between muscular asthenopia and eccentric ablation after photorefractive keratectomy (PRK). METHODS: Sixteen eyes of eight myopic patients whose muscular asthenopia was corrected by subjectively accepted spectacle prism after PRK, with visual acuity better than 0.8, were followed for 6 to 14 months. On the basis of preoperative and post-operative data and corneal topography, we calculated the total corrected corneal power using the Holladay formula and then measured the ablation eccentricity (h, millimeters) and its direction. According to the formula delta approximately equals Dh, the prism effective value (delta) caused by the eccentric ablation was computed and compared with the objectively accepted spectacle prism. RESULTS: The subjectively accepted spectacle prisms were similar to calculated values from the formula. Mean difference was 0.10 +/- 0.25delta. The direction of the subjectively accepted prism was in the direction of the ablation deviation. CONCLUSIONS: Eccentric ablation is an important cause of muscular visual asthenopia after PRK. The asthenopia may be corrected by spectacle prism. The spectacle prism value may be estimated by the formula delta approximately equals Dh.

Adult↗

PubMedDate not supplied

Allelic variation in the intron 2 and 3 of the MICA gene.

We have determined by sequencing the allelic variation in intron 2 and 3 of hte MICA gene for a total of 22 different alleles. Sequencing of introns was performed in two directions, using DNA from homozygous cell lines from families and from unrelated individuals. Intron 2 is 273 bp long and did in the alleles investigated not reveal any length polymorphism. We found a total of eight polymorphic positions which exhibit a strict biallelism, as it is also found in the polymorphisms for exon 2, 3 and 4 of MICA. Intron 3 is 586 bp long an required an additional set of primers placed near the middle of this intron in order to allow a complete bidirectional sequence. In intron 3, a total of 10 polymorphic positions were identified. Interestingly, we found two variants of the allele MICA*002 which are distinguished only by one basepair difference in intron 3. The variant MICA*002A is associated with HLA-B35 and B58, while the allele MICA*002B is associated with B38 and B39.

Alleles↗

PubMedDate not supplied

Structure, function and regulation of the mitochondrial peripheral-type benzodiazepine receptor.

Steroid biosynthesis begins with the transfer of cholesterol from intracellular stores into mitochondria. Through in vitro and in vivo studies using various steroidogenic cell models and with the help of pharmacological, biochemical, morphological and molecular approaches we demonstrated that the peripheral-type benzodiazepine receptor (PBR) is an 18 kDa mitochondrial protein that interacts with other proteins in the outer mitochondrial membrane to form a multimeric complex. PBR is required for the binding, uptake and release, upon ligand activation, of the substrate cholesterol. Thus, cholesterol becomes available to the inner mitochondrial membrane P450scc where steroid biosynthesis begins. The presence of mitochondrial PBR is also critical in maintaining outer mitochondrial membrane stability and in preventing apoptosis. Considering these functions of PBR and the fact that PBR is a ubiquitous protein, it is suggested that this drug receptor may serve as a target to control various mitochondrial and cell functions and to protect against experimentally or pathologically induced mitochondrial and cell toxicity.

Animals↗

PubMedDate not supplied

Glucose-insulin kinetics of the extravascular bioartificial pancreas. A study using microencapsulated rat islets.

The success of the extravascular bioartificial pancreas (BAP) is contingent on the rapid transfer of the glycemic signal across both an extravascular compartment and a semipermeable membrane and of insulin from the BAP to the recipient. To examine the possibility of microencapsulated islets such as the BAP to achieve satisfactory in vivo glucose-insulin kinetics, islets were isolated from Lewis rats, encapsulated in poly-L-lysine-alginate membranes, and isogenically transplanted into the peritoneal cavity of 14 streptozotocin induced diabetic rats. Fasting blood glucose (BG) was measured and intravenous glucose tolerance was tested at 8-10 weeks and compared with three control groups: 1) normal Lewis rats (n = 6); 2) untreated diabetic rats (n = 5); and 3) diabetic rats that received intraperitoneal implants of empty capsules (n = 4). Ten animals that received microencapsulated islets (5,271 +/- 431) promptly became normoglycemic, with a mean BG of 128 +/- 17 ng/dl 3 days after transplantation and maintained this level > 100 days. Intravenous glucose tolerance K-value for the group was 3.84 +/- 0.32 compared with 3.96 +/- 0.39 (p = 0.83) for the normal control group, and 0.60 +/- 0.12 (p < 0.01) and 0.40 +/- 0.15 (p < 0.01) for the diabetic control groups with and without empty capsules. The authors conclude from these results that, given sufficient beta-cell mass, a BAP without any vascular access can respond appropriately to an increase in blood glucose concentration, without overshoot hypoglycemia and within a lag lapse compatible with normal physiologic insulin delivery.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMedDate not supplied

Value of low-dose gallium-67 imaging in detection of non-Hodgkin's lymphoma recurrence.

We evaluated the usefulness of low-dose Ga-67 scintigraphy as a diagnostic tool for the detection of non-Hodgkin's lymphoma recurrence. Forty-six patients were included in this retrospective study. Anterior and posterior whole body images were obtained two or three days after the injection of 74 MBq of Ga-67. Inter- and intraobserver variability in scintigraphic imaging interpretation was analyzed using the kappa (kappa) statistics. Ga-67 scintigraphy allowed correct detection of recurrence in 18 of 22 events (sensitivity, 82%), and excluded relapse in 34 of 39 events (specificity, 87%). The positive predictive value was 0.78 and negative predictive value 0.89. All cases involving superficial lymph nodes (10/ 10) could be detected by Ga-67. Chest lesions were diagnosed with a sensitivity of 86% (6/7), bone and soft tissue 83% (5/6), and abdomen 80% (8/10). The sensitivity and specificity of CT were 91% (22/24) and 67% (8/12), respectively. In abdominal lesions, ultrasonography had sensitivity and specificity of 93% (14/15) and 94% (15/16), respectively. Kappa (kappa) statistics demonstrated good to strong inter- and intraobserver agreement in the interpretation of Ga-67 scintigraphy. The diagnostic results of low-dose Ga-67 scans, currently applied in Japan, were similar to those reported by the authors using high doses of 296 MBq to 370 MBq. Ga-67 scintigraphy, even at low dose, is useful in the detection of non-Hodgkin's lymphoma recurrence.

Adult↗