Human red blood cell Wright antigens: a genetic and evolutionary perspective on glycophorin A-band 3 interaction

The Wright (Wra/Wrb) blood group polymorphism is defined by an allelic change (Lys658Glu) in the band 3 protein; nevertheless, the Wrb antigen apparently requires glycophorin A (GPA) for surface presentation. To gain insight into the structural basis for this protein-protein interaction and delineate its relationship with Wrb antigen expression, we investigated GPA and band 3 sequence polymorphisms occurring in rare humans and nonhuman primates. The lack of GPA or amino acid residues 59 through 71 of GPA results in the absence of Wrb from human red blood cells (RBCs) exhibiting the MkMk, En(a-), or MiV phenotype. However, the SAT homozygous cells carried a Glu658 form of band 3 and a hybrid glycophorin with the entire GPA extramembrane domain from residues 1 through 71, yet expressed no Wrb antigen. This finding suggests that formation of the Wrb antigenic structure is dependent on protein folding and that the transmembrane junction of GPA is important in maintaining the required conformation. Comparative analyses of GPA and band 3 homologues led to the identification in the interacting regions of conserved and dispensable amino acid residues that correlated with the Wrb positive or negative status on nonhuman primates. In particular, the chimpanzee RBCs cells expressed Wrb and the Glu658 form of band 3, which is identical to humans, but their GPA contained the Gly rather than Arg residue at position 61. Taken together, the results suggest that (1) Arg61 of GPA and the proposed Arg61-Glu658 charge pair are not crucial for Wrb antigen exhibition and (2) the role of GPA for interaction with band 3, including Glu658, probably involves a number of amino acid residues located in the alpha-helical region and transmembrane junction.     

Neck neoplasms: MR imaging. Part I. Initial evaluation

Untreated neoplasms of the neck (tumors of the oropharynx, supraglottic area, carotid body, and thyroid, in addition to malignant lymphadenopathy) were evaluated in 23 patients with magnetic resonance (MR) imaging. The results were compared with computed tomographic (CT) scans in 20 patients. Contrast between tumor and fat was best on relatively T1-weighted images (500/30-35 [TR msec/TE msec]), whereas separation of tumor and muscle was best with relatively T2-weighted pulse sequences (1,500/90). Balanced images (1,500/30-35) provided best overall image quality and best demonstrated vascular anatomy. MR imaging was usually superior to CT in showing the relationship of tumor mass to muscle. MR imaging and contrast material-enhanced CT were equivalent in most patients in defining vascular anatomy, but MR imaging was superior when intravenous contrast material was not administered. However, CT was more helpful in showing bone and cartilage anatomy, and in some patients CT also was better in showing airway abnormalities. Despite these limitations, MR imaging is a promising imaging technique for studying neoplasms of the neck.     

Analgesic Effect of Oral Glucose in Neonates

The International Association for the Study of Pain, has defined pain as “an unpleasant sensory and emotional experience connected with actual or potential tissue damage or described in terms of such damage”. It was thought that the newborn baby does not experience pain because of incompletely developed nervous system. However, it has been shown that neurological system known to be associated with pain transmission and modulation, is intact and functional. A study was conducted in our center to study the analgesic effect of administration of oral glucose in various concentrations, in neonates undergoing heel punctures, for collection of blood for investigations. This was compared with the analgesic effects of breast milk (which contains lactose). 125 full term normal neonates with no history of birth asphyxia or underlying neurological abnormality, requiring heel punctures for collection of blood for various investigations were selected for the study. They were matched for gestational age, birth weight and sex distribution and divided into 5 groups of 25 each. One group comprised control subjects and was administered sterile water. 3 groups were administered 1 ml of varying strengths of glucose solutions i.e. 10%, 25% and 50% respectively. The last group was given 1 ml of expressed breast milk (EBM). Prior to heel pricks, state of arousal, baseline heart rate (HR) and transcutaneous oxygen saturation (SpO₂) were recorded by pulse oximeter in each neonate. Autolet, a mechanical device for capillary sampling, was used for heel pricks to give equal strength of painful stimulus in each procedure. Audio tape recorder was used to record the cry. The oral solution was administered slowly over 30 seconds by means of a syringe placed in the mouth. Heel puncture was done after 2 minutes, taking all aseptic precautions. HR and SpO₂ were monitored using pulse oximeter. Pain response was assessed, by recording duration of crying, change in HR, change in SpO₂ and facial action score after the procedure. Mean duration of cry and total cry over 5 minutes was significantly less in groups given 25% and 50% glucose solutions as compared to the control group and babies given EBM. Difference in mean increase in HR, fall in SpO₂ were statistically significant between control group, EBM group and neonates given 25% and 50% glucose solutions respectively. Compared to control group, all other administered solutions (10%, 25%, 50% glucose and EBM) were found to reduce physiological and behavioral responses in neonates undergoing heel punctures. 25% and 50% glucose solutions were found to have maximal analgesic effect and both were found to be equally effective. EBM and 10% glucose solution have an equal analgesic effect but less than 25% or 50% glucose. This simple, cheap and safe method of oral analgesia can be easily used in neonates undergoing heel prick procedures during routine neonatal care.Key Words: Analgesic effect, Breast milk, Glucose, Neonates     

Vasectomy surgical techniques in South and South East Asia

Background

Simple ligation of the vas with suture material and excision of a small vas segment is believed to be the most common vasectomy occlusion technique performed in low-resource settings. Ligation and excision (LE) is associated with a risk of occlusion and contraceptive failure which can be reduced by performing fascial interposition (FI) along with LE. Combining FI with intra luminal thermal cautery could be even more effective. The objective of this study was to determine the surgical vasectomy techniques currently used in five Asian countries and to evaluate the facilitating and limiting factors to introduction and assessment of FI and thermal cautery in these countries.

Methods

Between December 2003 and February 2004, 3 to 6 major vasectomy centers from Cambodia, Thailand, India, Nepal, and Bangladesh were visited and interviews with 5 to 11 key informants in each country were conducted. Vasectomy techniques performed in each center were observed. Vasectomy techniques using hand-held, battery-driven cautery devices and FI were demonstrated and performed under supervision by local providers. Information about interest and open-mindedness regarding the use of thermal cautery and/or FI was gathered.

Results

The use of vasectomy was marginal in Thailand and Cambodia. In India, Nepal, and Bangladesh, vasectomy was supported by national reproductive health programs. Most vasectomies were performed using the No-Scalpel Vasectomy (NSV) technique and simple LE. The addition of FI to LE, although largely known, was seldom performed. The main reasons reported were: 1) insufficient surgical skills, 2) time needed to perform the technique, and 3) technique not being mandatory according to country standards. Thermal cautery devices for vasectomy were not available in any selected countries. Pilot hands-on assessment showed that the technique could be safely and effectively performed by Asian providers. However, in addition to provision of supplies, introducing cautery with FI could be associated with the same barriers encountered when introducing FI in combination with LE.

Conclusion

Further studies assessing the effectiveness, safety, and feasibility of implementation are needed before thermal cautery combined with FI is introduced in Asia on a large scale. Until thermal cautery is introduced in a country, vasectomy providers should practice LE with FI to maximize effectiveness of vasectomy procedure.     

异叶梁王茶甙Ⅲ和Ⅳ的结构

继前报后,又从异叶梁王茶[Nothopanax davidii(France)Harms]树皮中分离得到两种五环三萜皂甙。经化学和波谱(IR,¹HNMR,~(13)CHMR,¹H-¹HCOSY,¹³C-¹H COSY,MS)分析,分别鉴定为3-O-α-(2’,4’-O-二乙酰基)-L-吡喃阿拉伯糖-3β-羟基齐墩果-12-烯-28,29-双羧酸-28-O-[α-L-吡喃鼠李糖(1-4)-β-D-吡喃葡萄糖(1—6)-β-D-吡喃葡萄糖]酯甙(Ⅲ),命名为异叶梁王茶甙Ⅲ和3-O-β-(2-O-乙酰基)-D-吡喃木糖-3β-羟齐墩果-12-烯-28,29-双羧酸甙(Ⅳ),命名为异叶梁王茶甙Ⅳ。这两种皂甙均系首次从植物中分出的新化合物。     

CT of the pulmonary nodule: a cooperative study

To evaluate the role of computed tomography (CT) in the investigation of pulmonary nodules, a special reference phantom that enabled CT densitometric measurements independent of variations between scanners and patients was used in ten institutions. A total of 384 nodules not considered calcified by conventional methods were examined; 118 (31%) proved to be benign, and in 65 of these (55%), unsuspected calcification was demonstrated. In 28 of the 65, definite calcification could be identified on thin-section CT scans by simple inspection of the scans at narrow windows. In the remaining 37, presence of calcification could not be clearly established without comparison with the reference CT number from the calibration phantom. CT was most effective in establishing the benignancy of nodules 3 cm or less in diameter and those with discrete or smooth margins. CT rarely yields a confident diagnosis of benign disease in larger nodules and in those with irregular or spiculated borders. After review of prior spot radiographs, low kilovolt peak spot radiographs, and conventional tomograms, the authors conclude that thin-section CT aided by a reference phantom in equivocal cases should be an integral part of the diagnostic approach to the pulmonary nodule.