Cloning of glycoprotein IIIa cDNA from human erythroleukemia cells and localization of the gene to chromosome 17

Platelet aggregation requires the binding of adhesive proteins such as fibrinogen to the heterodimer of membrane glycoproteins IIb (GPIIb) and IIIa (GPIIIa). Human erythroleukemia (HEL) cells synthesize both GPIIb and GPIIIa. Using poly(A+) RNA purified from HEL cells, we constructed a cDNA library in the lambda gt10 phage vector. This library was screened with a 38mer oligonucleotide derived from a platelet GPIIIa peptide, and three overlapping cDNAs were isolated. The three inserts encompassed 3.5 kilobases (kb), including the entire coding region of mature GPIIIa (2,286 basepairs, bp) and 1.3 kb of 3' untranslated sequence. All 222 residues determined directly from platelet GPIIIa tryptic peptides exactly matched the HEL cell-deduced amino acid sequence. The HEL cell sequence matched a previously reported endothelial cell cDNA sequence except for eight nucleotides. Five of these nucleotide differences were silent changes consistent with genetic polymorphisms. The other three differences resulted in changes in the deduced amino acid sequence of GPIIIa; reexamination of the endothelial cell cDNA sequence in these three areas revealed that it is actually identical to the HEL cell sequence. The virtual identity of the endothelial and HEL cell cDNA sequences provides direct evidence that GPIIIa is a subunit common to cell-adhesion receptors present in more than one cell type. We localized the gene for GPIIIa to chromosome 17, the same chromosome to which we had previously mapped the gene for GPIIb.     

The functional and structural changes in the basilar artery due to overpressure blast injury

Overpressure blast-wave induced brain injury (OBI) leads to progressive pathophysiologic changes resulting in a reduction in brain blood flow, blood brain barrier breakdown, edema, and cerebral ischemia. The aim of this study was to evaluate cerebral vascular function after single and repeated OBI. Male Sprague-Dawley rats were divided into three groups: Control (Naive), single OBI (30 psi peak pressure, 1 to 2 msec duration), and repeated (days 1, 4, and 7) OBI (r-OBI). Rats were killed 24 hours after injury and the basilar artery was isolated, cannulated, and pressurized (90 cm H₂O). Vascular responses to potassium chloride (KCl) (30 to 100 mmol/L), endothelin-1 (10⁻¹² to 10⁻⁷ mol/L), acetylcholine (ACh) (10⁻¹⁰ to 10⁻⁴ mol/L) and diethylamine-NONO-ate (DEA-NONO-ate) (10⁻¹⁰ to 10⁻⁴ mol/L) were evaluated. The OBI resulted in an increase in the contractile responses to endothelin and a decrease in the relaxant responses to ACh in both single and r-OBI groups. However, impaired DEA-NONO-ate-induced vasodilation and increased wall thickness to lumen ratio were observed only in the r-OBI group. The endothelin-1 type A (ET_A) receptor and endothelial nitric oxide synthase (eNOS) immunoreactivity were significantly enhanced by OBI. These findings indicate that both single and r-OBI impairs cerebral vascular endothelium-dependent dilation, potentially a consequence of endothelial dysfunction and/or vascular remodelling in basilar arteries after OBI.     

Is homozygous α-thalassaemia a lethal condition in the 1990s?

Two cases of homozygous α-thalassaemia who received active treatment in accordance with parental wishes are reported. One infant survived and the other, although successfully weaned off mechanical respiratory support, unexpectedly developed portal vein thrombosis and died. Homozygous a-thalassaemia, a condition previously considered to be universally fatal, and an indication for therapeutic abortion, is now potentially curable with advances in diagnostic technology and treatment. However, active management of these cases raises serious ethical questions and has major financial implications on the health-care system. Invasive prenatal and intensive postnatal interventions should remain experimental and cannot be recommended as routine clinical practice until the questions of long-term neurodevelopmental outcome, and the morbidity and mortality associated with bone-marrow transplantation have been fully addressed. As a result of advances in information technology, more and more parents of affected foetuses are likely to request active treatment.     

Targeted Disruption of NF1 in Osteocytes Increases FGF23 and Osteoid With Osteomalacia‐like Bone Phenotype

Neurofibromatosis type 1 (NF1, OMIM 162200), caused by NF1 gene mutations, exhibits multi‐system abnormalities, including skeletal deformities in humans. Osteocytes play critical roles in controlling bone modeling and remodeling. However, the role of neurofibromin, the protein product of the NF1 gene, in osteocytes is largely unknown. This study investigated the role of neurofibromin in osteocytes by disrupting Nf1 under the Dmp1‐promoter. The conditional knockout (Nf1 cKO) mice displayed serum profile of a metabolic bone disorder with an osteomalacia‐like bone phenotype. Serum FGF23 levels were 4 times increased in cKO mice compared with age‐matched controls. In addition, calcium‐phosphorus metabolism was significantly altered (calcium reduced; phosphorus reduced; parathyroid hormone [PTH] increased; 1,25(OH)₂D decreased). Bone histomorphometry showed dramatically increased osteoid parameters, including osteoid volume, surface, and thickness. Dynamic bone histomorphometry revealed reduced bone formation rate and mineral apposition rate in the cKO mice. TRAP staining showed a reduced osteoclast number. Micro‐CT demonstrated thinner and porous cortical bones in the cKO mice, in which osteocyte dendrites were disorganized as assessed by electron microscopy. Interestingly, the cKO mice exhibited spontaneous fractures in long bones, as found in NF1 patients. Mechanical testing of femora revealed significantly reduced maximum force and stiffness. Immunohistochemistry showed significantly increased FGF23 protein in the cKO bones. Moreover, primary osteocytes from cKO femora showed about eightfold increase in FGF23 mRNA levels compared with control cells. The upregulation of FGF23 was specifically and significantly inhibited by PI3K inhibitor Ly294002, indicating upregulation of FGF23 through PI3K in Nf1‐deficient osteocytes. Taken together, these results indicate that Nf1 deficiency in osteocytes dramatically increases FGF23 production and causes a mineralization defect (ie, hyperosteoidosis) via the alteration of calcium‐phosphorus metabolism. This study demonstrates critical roles of neurofibromin in osteocytes for osteoid mineralization. © 2017 American Society for Bone and Mineral Research.     

Integration of mental health services into primary care overcomes ethnic disparities in access to mental health services between black and white elderly.

OBJECTIVE: The authors evaluated whether the integration of mental health into primary care overcomes ethnic disparities in access to and participation in mental health (MH) and substance abuse (SA) treatment. METHODS: The authors conducted site-specific analysis of a multisite clinical trial to compare participation of black and white elderly in an integrated model of care (all MH/SA services are provided at primary care clinics) versus an enhanced referral model of care (all MH/SA services are provided at specialized MH clinics). In all, 183 elderly (56% black) diagnosed with depression (82%), anxiety (32%), and/or problem drinking (22%) were randomized. RESULTS: Blacks in the integrated arm were significantly more likely to have at least one MH/SA visit (77.5%) relative to blacks in the enhanced referral arm (22%; adjusted odds ratio [OR]: 14.13; confidence interval [CI]: 4.76-41.95, Wald chi(2): 22.75, df = 1, p <0.0001). There was no statistically significant difference between whites in the integrated treatment arm (66.6%) and whites in the enhanced referral arm (46.9%, adjusted OR: 2.98; CI: 0.98-9.06, Wald chi(2): 3.72, df = 1, p = 0.05). In the enhanced referral arm, blacks had a significantly smaller number of overall MH/SA visits (mean [SD]: 2.08 [5.28]) relative to whites (mean [SD]: 5.31 [7.76], adjusted incident rate ratio [IRR]: 2.87; CI: 1.06-7.73, Wald chi(2): 4.37, df = 1, p = 0.03). In the integrated arm, there was no statistically significant difference between blacks (mean [SD]: 3.22 [3.71]) and whites (mean [SD]: 2.75 [4.29], adjusted IRR: 0.58; CI: 0.25-1.33, Wald chi(2): 1.64, df = 1, p = 0.20). For both groups, time between baseline evaluation to first MH/SA visit was significantly shorter in the integrated treatment arm (for blacks: mean days [SD]: 31.06 [28.66]; for whites: mean days [SD]: 22.18 [33.88]) than in the enhanced referral arm (mean [SD]: 62.45 [43.53], adjusted hazard ratio [HR]: 7.82; CI: 3.65-16.75, Wald chi(2): 28.02, df = 1, p <0.0001; mean [SD]: 63.46 [32.41], adjusted HR: 2.48; CI: 1.20-5.13, Wald chi(2): 6.02, df = 1, p = 0.01, respectively). CONCLUSION: An integrated model of care is particularly effective in improving access to and participation in MH/SA treatment among black primary care patients.     

Thrombotic events in metastatic colorectal cancer patients treated with leucovorin,fluorouracil and irinotican (FOLFIRI) plus bevacizumab

Objective

To determine the incidence and risk factors for thrombotic events (TEs) in patients with metastatic colorectal cancer (mCRC) who received bevacizumab (BV) and FOLFIRI (leucovorin, fluorouracil and irinotican) compared to FOLFIRI alone.

Methods

Single institution retrospective study of 450 mCRC patients who received either BV plus FOLFIRI or FOLFIRI alone between April 2004 and August 2012. Demographics, TE risk factors, and treatment data were abstracted from patients’ records. Multivariate analysis was used to identify factors that contributed to thromboembolism.

Results

Two-hundred-sixty-one mCRC patients received BV plus FOLFIRI [64.8% males, mean body mass index (BMI) of 27.6] compared to 189 control patients who received FOLFIRI alone (61.9% males, BMI 27.2). The incidence of TEs was 14.9% in the BV plus FOLFIRI group, compared to 15.9% in the control group. Multivariate analysis controlling for age, BMI, gender, malignancy, metastatic sites, line of treatment, and risk factors did not suggest a significant increase in the risk of TE with the addition of BV (OR =0.83 95% CI: 0.40-1.70; P=0.602). No difference in the site of TEs was observed between the treatment groups. The only statistically significant risk factor for thrombosis in the FOLFIRI plus BV group was increased BMI (OR =1.05; 95% CI: 1.01-1.10; P=0.01).

Conclusions

This study does not support a significant increase in the risk of TE in patients with mCRC who received BV in addition to FOLFIRI. Increased BMI may be a risk factor for thrombosis in patients treated with BV.     

Computed tomography for cervical spine trauma. The impact of MDCT on fracture detection and dose deposition

A multidetector computed tomography (MDCT) was installed in our department. Referral rates, examination protocols and detection rates of abnormal findings in CT examinations for cervical spine trauma 6 months before and 6 months after MDCT installation were compared to look for changes in practice. Retrospective analysis of all CT cervical spine examinations in patients with multiple trauma over two contiguous 6-month periods: from July 2003 to December 2003 (helical CT) and from January 2004 to June 2004 (MDCT). Variables recorded were number of CT examinations performed, scan plane coverage and traumatic abnormalities detected. Phantom dosimetry measurements for cervical spine examination in both helical CT and MDCT were compared. One hundred and fifty four patients underwent cervical spine CT during these periods. Helical CT period: of 91 patients undergoing CT cervical spine examination for trauma, 65 (71%) were complete cervical examinations and 26 (29%) were level-specific examinations. Eight patients (9%) had cervical spine fracture, six of which were apparent on radiographs. Dose estimations for thyroid, lens and breast were 24.76, 1.86 and 0.21 mGy, respectively, for complete cervical spine examinations. MDCT period: of 63 patients who underwent CT cervical spine examination for trauma, 61 (97%) were complete examinations and 2 (3%) were level-specific examinations. Six patients (11%) had cervical spine fracture, three of which were apparent on radiographs. Dose estimations for thyroid, lens and breast were 75.8, 9.7 and 0.7 mGy, respectively, for complete cervical spine examinations, which were notably higher than those for helical CT. After installation of MDCT, clinical requests for complete examination of the cervical spine following trauma increased. This changing trend resulted in a significantly higher radiation dose to thyroid, lens and breast.