Dynamic platelet function on von Willebrand factor is different in preterm neonates and full-term neonates: changes in neonatal platelet function.

Essentials It is unclear if platelet function differs between preterm and full-term neonates. Platelet behavior was characterized using a flow-based assay on von Willebrand Factor (VWF). Preterms had increased platelet interaction with VWF and glycoprotein Ibα expression. Platelets from preterm neonates behave differently on VWF compared to full-term neonates. SUMMARY: Background Very low birth weight (VLBW) preterm neonates have an increased risk of hemorrhage-related morbidity and mortality as compared with their full-term counterparts. It is unclear whether platelet function differs between preterm and full-term neonates. This is partly because of the large volumes of blood required to perform standard platelet function tests, and the difficulty in obtaining such samples in neonates. Objectives This study was designed to characterize platelet behavior in neonates with a physiologic flow-based assay that quantifies platelet function in microliter volumes of blood under arterial shear. Methods Blood from VLBW preterm neonates of ≤ 32 weeks' gestation (n = 15) and full-term neonates (n = 13) was perfused under arterial shear over surface-immobilized von Willebrand factor (VWF). Platelet behavior was recorded by digital-image microscopy and analyzed. Surface expression of platelet glycoprotein (GP) Ibα and GPIIIa of VLBW preterm and full-term neonates was also measured. Results VLBW preterm neonates had increased numbers of platelets interacting with VWF, and increased GPIbα expression on the platelet surface. Despite the increased numbers of VWF interactions as reflected by flow-driven platelet translocation along the protein surface, no significant differences were observed in the numbers of platelets that adhered in a stationary fashion to VWF. Platelets from VLBW preterm neonates and those from full-term neonates behaved differently on VWF. Conclusions These differences in platelet function may contribute to the higher incidence of bleeding observed in VLBW preterm neonatal populations, or may represent a compensatory mechanism to counteract this risk of bleeding.

A rare benign renal tumour presenting as polycythaemia in a teenage girl.

We present the case of a 15-year-old girl who presented with polycythemia. CT abdomen revealed an enhancing mass in the upper pole of her left kidney with features suggestive of renal cell carcinoma. She underwent a laparoscopic radical nephrectomy. Histology demonstrated a well circumscribed, focally encapsulated, round blue cell tumour showing areas of microcalcifications and numerous psammoma bodies. Imunostaining showed diffuse positive staining for CD 57. This was consistent with a diagnosis of metanephric adenoma a rare benign epithelial renal tumour.

Endovascular brachytherapy: dosimetry and dose-area analysis of various radiation sources.

With the increase in popularity of endovascular brachytherapy for prevention of restenosis following coronary angioplasty, it remains to be determined which isotope and isotope form is the most ideal. An issue concerning the use of wire sources is the influence of the centering of the wire on dose uniformity across the artery wall and the potential problems this can lead to in terms of underdosage of the target tissues. In this investigation, the dosimetric characteristics of three currently used sources (gamma-emitting 192Ir wire; beta-emitting 32P wire; and beta-emitting 188Re solution) were determined with EGS4 Monte Carlo. The dose results were then used to determine the dose-area relationships for the three sources in arteries with concentric and non-concentric lumens/walls, including situations in which the wire sources are moved away from the centre of the artery. It is found that, in order to ensure dose uniformity, centering is substantially more important for beta-emitting wire sources. This is highlighted most significantly in the case of an example large irregular artery. Although the suitability of a source depends on many criteria (e.g., cost, availability, radiation protection, possible radiation-induced late effects), the problem of centering a wire source in possibly large and/or irregular arteries is greatly eased by the use of a gamma-emitting source.

Cloning, sequencing and expression of the gene for flavodoxin from Megasphaera elsdenii and the effects of removing the protein negative charge that is closest to N(1) of the bound FMN.

The gene for the electron-transfer protein flavodoxin has been cloned from Megasphaera elsdenii using the polymerase chain reaction. The recombinant gene was sequenced, expressed in an Escherichia coli expression system, and the recombinant protein purified and characterized. With the exception of an additional methionine residue at the N-terminus, the physico-chemical properties of the protein, including its optical spectrum and oxidation-reduction properties, are very similar to those of native flavodoxin. A site-directed mutant, E60Q, was made to investigate the effects of removing the negatively charged group that is nearest to N(1) of the bound FMN. The absorbance maximum in the visible region of the bound flavin moves from 446 to 453 nm. The midpoint oxidation-reduction potential at pH 7 for reduction of oxidized flavodoxin to the semiquinone E2 becomes more negative, decreasing from -114 to -242 mV; E1, the potential for reduction of semiquinone to the hydroquinone, becomes less negative, increasing from -373 mV to -271 mV. A redox-linked pKa associated with the hydroquinone is decreased from 5.8 to < or = 4.3. The spectra of the hydroquinones of wild-type and mutant proteins depend on pH (apparent pKa values of 5.8 and < or = 5.2, respectively). The complexes of apoprotein and all three redox forms of FMN are much weaker for the mutant, with the greatest effect occurring when the flavin is in the semiquinone form. These results suggest that glutamate 60 plays a major role in control of the redox properties of M. elsdenii flavodoxin, and they provide experimental support to an earlier proposal that the carboxylate on its side-chain is associated with the redox-linked pKa of 5.8 in the hydroquinone.

Serum amyloid A in the assessment of early inflammatory arthritis.

OBJECTIVE: Acute phase serum amyloid A (A-SAA) has been reported to be more sensitive than C-reactive protein (CRP) as a marker of disease activity. It may function in immune regulation and is linked to the development of secondary amyloidosis. We investigated the profile of A-SAA in early inflammatory arthritis and compared A-SAA with CRP and erythrocyte sedimentation rate (ESR) in relation to diagnosis and disease activity. METHODS: Using a sensitive and specific ELISA, A-SAA was measured in the serum of 140 patients with early arthritis (disease duration 2 weeks to 24 mo, mean 6 mo). CRP was determined using a standard ELISA; ESR and clinical disease activity variables were also recorded. RESULTS: Sixty-four patients had rheumatoid arthritis (RA), 19 psoriatic arthritis (PsA), 28 undifferentiated arthritis (UA), and 29 other forms of arthritis. A-SAA levels correlated with both CRP (r = 0.73, p = 0.0001) and ESR (r = 0.6, p = 0.0001). The magnitude of the A-SAA response was greater than either the CRP or ESR, and very high A-SAA levels were observed in disease as early as 2 weeks. Highest A-SAA concentrations occurred in RA (median 70.3 mg/l, maximum 1542) compared with the other groups (medians, PsA: 33 mg/l; UA: 12.3 mg/l; other arthritis: 11.2 mg/l), with values > 520 mg/l observed exclusively in RA. A-SAA, unlike CRP or ESR, could distinguish patients with a final diagnosis of RA from those who had persistent UA. In RA, A-SAA provided the strongest correlations with clinical measurements of disease activity. Clinical improvement was also best represented by A-SAA, while disease deterioration was associated with a significant increase in A-SAA values, but not CRP or ESR. CONCLUSION: Compared with ESR or CRP, A-SAA correlates best with markers of disease activity, and in patients with recent onset arthritis, very high levels of SAA occur exclusively in RA. As A-SAA is sensitive to change and accurately reflects alterations in disease status, it is the best marker available for the assessment of inflammatory joint disease.

Owner satisfaction with partial mandibulectomy or maxillectomy for treatment of oral tumors in 27 dogs.

Twenty-seven dogs with oral tumors were treated with either rostral mandibulectomy, partial mandibulectomy, or partial maxillectomy. Owner satisfaction with the respective surgical procedure was assessed by telephone survey; 85% of owners were satisfied with the decision to treat their dogs. The percentage of satisfied owners was directly proportional to the increase in pet life span. Although difficulty in eating was noted for 12 (44%) of 27 dogs, pain was perceived to be reduced by the surgery for most animals. All owners found the cosmetic appearances of their dogs acceptable after facial hair regrew. The quality of the pets' lives was perceived by the owners to be most improved after rostral mandibulectomy and least improved after partial maxillectomy.

Primary care referral management: a marketing strategy for hospitals.

With increasing competition among hospitals, primary care referral development and management programs offer an opportunity for hospitals to increase their admissions. Such programs require careful development, the commitment of the hospital staff to the strategy, an integration of hospital activities, and an understanding of medical practice management.

Group assertiveness training for alcoholics.

Six men alcoholics showed increased assertiveness and improvement in social and occupational status after attending a group assertiveness training program.