Zn DEFICIENCY AGGRAVATES HYPERTENSION IN SPONTANEOUSLY HYPERTENSIVE RATS: POSSIBLE ROLE OF Cu/Zn-SUPEROXIDE DISMUTASE

Using spontaneously hypertensive rats (SHR) fed a standard or a Zn-deficient diet for 4 weeks, we examined whether Zn deficiency affects systemic blood pressure (BP) levels in a genetically hypertensive state through a fall in the activity of Cu/Zn-superoxide dismutase (SOD). SHR fed a Zn-deficient diet had a progressive increase in systolic BP during the dietary conditioning. Consequently, SHR fed a Zn-deficient diet exhibited significantly increased levels of systolic BP by 2 weeks after the start of dietary treatment when compared with SHR fed a standard diet. Similarly, levels of basal mean arterial pressure (MAP) observed at the end of dietary treatment were SHR fed a Zn-deficient diet>SHR fed a standard diet. Administration of the nitric oxide synthase (NOS) inhibitor, L-NAME, caused an increase in MAP levels in the two groups of rats, demonstrating the involvement of the vasodilator, nitric oxide (NO), in the regulation of systemic BP in a genetically hypertensive state. The expression of endothelial (e) NOS mRNA and protein in the thoracic aorta paralleled basal MAP levels in the two groups of rats, suggesting the counter-regulation of eNOS against the developed hypertensive state in SHR fed a Zn-deficient diet. On the other hand, administration of the superoxide scavenger, tempol (a SOD mimetic compound), led to a decrease in MAP levels in the two groups of rats, indicating the participation of the oxygen free radical, superoxide, in an increase in systemic BP in a genetically hypertensive state. As reported recently, the mechanism involved is due likely to a decrease in the action of the vasodilator, NO, based on the formation of peroxynitrite coming from the non-enzymatic reaction of superoxide and NO. In addition, tempol treatment completely restored MAP levels in SHR fed a Zn-deficient diet to levels comparable to those observed in SHR fed a standard diet, indicating that a further increase in systemic BP levels seen in SHR fed a Zn-deficient vs. a standard diet is presumably brought by a reduction in the action of the vasodilator, NO, resulting from an increase in the action of superoxide. The activity of the superoxide scavenger, Cu/Zn-SOD, in the thoracic aorta was significantly decreased in SHR fed a Zn-deficient diet relative to SHR fed a standard diet. It appears that a decrease in the activity of Cu/Zn-SOD observed in the thoracic aorta of SHR fed a Zn-deficient diet at least in part plays a role in an increase in the action of superoxide in this model. Thus, Zn deficiency may be a factor to develop genetic hypertension presumably through the oxidative stress caused by superoxide.     

甘露聚糖、壳聚糖、α-酸性糖蛋白和姜黄素对脂蛋白(a)和去唾液酸脂蛋白(a)代谢影响的对比分析

分析多糖和姜黄素对脂蛋白 (a)和去唾液酸脂蛋白 (a)代谢的影响 ,从刺猬腋下静脉注入甘露聚糖、壳聚糖、α -酸性糖蛋白和姜黄素 ,2min后注射12 5I-脂蛋白 (a)或12 5I-去唾液酸脂蛋白 (a) ,1h后处死动物 ,测定血、肝、肾、脾、胆汁和肾上腺的同位素含量。结果发现 ,脂蛋白 (a)去唾液酸后能大量进入肝脏 ,加速在体内的分解代谢 ,使血中浓度迅速降低。α -酸性糖蛋白抑制组织对脂蛋白 (a)和去唾液酸脂蛋白 (a)的摄入 ,使血中脂蛋白 (a)和去唾液酸脂蛋白 (a)含量显著增高。壳聚糖和姜黄素增加肝脏和肾上腺对脂蛋白 (a)的摄取 ,使血中脂蛋白 (a)含量略降低 ,但对去唾液酸脂蛋白 (a)代谢无明显影响。甘露聚糖增加脾脏对脂蛋白 (a)的摄取 ,减少胆囊中脂蛋白 (a)含量 ,但增加肾脏和胆囊对去唾液酸脂蛋白 (a)的摄取 ,降低肾上腺对去唾液酸脂蛋白 (a)的摄取。结果提示 ,脂蛋白 (a)去唾液酸后能使脂蛋白 (a)分解代谢加快 ,脂蛋白 (a)分子中的唾液酸在结构稳定中起重要的作用。α -酸性糖蛋白抑制脂蛋白 (a)和去唾液酸脂蛋白 (a)代谢 ,而壳聚糖和姜黄素则促进脂蛋白 (a)代谢     

Influence of Tool Geometry and Process Parameters on Torque,Temperature, and Quality of Friction Stir Welds in Dissimilar Al Alloys

In the current investigation, the influence of the tool geometry, the position of the materials in the joint, the welding speed on the temperature and torque developed, and on the quality of the welds in dissimilar and tri-dissimilar T joints were analysed. The aluminium alloys used were AA2017-T4, AA6082-T6, and AA5083-H111 and the friction stir welds were performed with identical shoulder tools, but with either a pin with simple geometry or a pin with progressive geometry. Progressive pin tools proved to be a viable alternative in the production of dissimilar and tri-dissimilar welds, as they provide a larger tool/material friction area and a larger volume of dragged material, which promotes an increase in the heat generated and a good mixing of the materials in the stir zone, although they require a higher torque. Placing a stronger material on the advancing side also results in a higher temperature in the stir zone but requires higher torque too. The combination of these factors showed that tools with a progressive pin provide sound dissimilar and tri-dissimilar welds, unlike single-pin tools. The increase in the welding speed causes the formation of defects in the stir zone, even in tri-dissimilar welds carried out with a tool with a progressive pin, which impairs the fatigue strength of the welds.     

Improved On-Site Characterization of Arsenic in Gypsum from Waste Plasterboards Using Smart Devices

The impurities in waste plasterboards, a product of ethical demolition, are a serious problem for their recycling. Plasterboards, the wall materials used in old buildings, are often recycled into gypsum powder for various applications, including ground stabilization. However, this powder contains various chemical impurities from the original production process of the gypsum itself, and such impurities pose a risk of polluting the surrounding soil. Here, we present a simple method for verifying the presence of arsenic, a harmful element in recycled gypsum that is suitable for use at demolition sites. First, we developed a simple pretreatment method using a cation-exchange resin to dissolve insoluble gypsum suspended in water by exploiting a chemical equilibrium shift, and we estimated the quantity suitable for releasing the arsenic from arsenic-containing gypsum. This pretreated solution could then be tested with a conventional arsenic test kit by observing the color changes in the test paper using the image sensor of a smart device. This simple method could determine a wide range of arsenic quantities in the gypsum, which would be helpful for monitoring arsenic in recycled gypsum powder, thereby supporting the development of a safe circular economy for waste plasterboards.     

Eukaryotic and prokaryotic stomatins: the proteolytic link

The 32kD membrane protein stomatin was first studied because it is deficient from the red cell membrane in two forms of the class of haemolytic anaemias known as "hereditary stomatocytosis." The hallmark of these conditions is a plasma membrane leak to the monovalent cations Na+ and K+: the protein is missing only in the most severely leaky of these conditions. No mutation has ever been found in the stomatin gene in these conditions. Stomatin-like proteins have been identified in all three domains of biology, yet their function remains enigmatic. Although the murine knock-out is without phenotype, we have identified a family showing a splicing defect in the stomatin mRNA, in which affected children showed a catastrophic multisystem disease not inconsistent with the now-known wide tissue distribution of stomatin. We report here a study of strongly homologous stomatin-like genes in prokaryotes, which reveals a close connection with a never-studied gene erroneously known as "nfed." This gene codes for a hydrophobic protein with a probable serine protease motif. It is possible that these stomatin-like genes and those which are known as"nfed" form an operon, suggesting that the two protein products are aimed at a common function. The corollary is that stomatin could be a partner protein for a membrane-bound proteolytic process, in both prokaryotes and in eukaryotes generally: this idea is consistent with experimental evidence.     

Arterial Oxygen Saturation in Severely Disabled People: Effect of Oral Feeding in the Sitting Position

Control of the circulatory and respiratory systems is especially important in severely disabled people. The purpose of this study was to clarify the response of hemoglobin oxygen saturation level (SpO₂), pulse rate, and respiratory rate during oral feeding in severely disabled persons. Continuous measurement of these variables was done by pulse oximetry and respiratory inductance plethysmography under two experimental settings in eight severely disabled persons aged 14–28 yrs. Setting I consisted of the following three procedures: (a) a 30-min period in the supine position, (b) a 50-min period in a sitting position, and (c) a 30-min period in the supine position. Setting II consisted of the following four procedures: (a) a 30-min period before the meal in the supine position, (b) a nonspecified period in a sitting position during which the meal was taken, (c) a 30-min period after the meal in the same sitting position, and (d) a 30-min period in the supine position. Results showed that mean SpO₂ level decreased and mean pulse rate increased during the meal in almost all subjects. In many cases, pulse rate and SpO₂ level did not return to baseline values in the sitting position after the meal. These findings indicate that oral feeding of severely disabled persons in a sitting position places considerable stress on the circulatory system, the effects of which may last after the meal in some cases.     

甘露聚糖、壳聚糖、α-酸性糖蛋白和姜黄素对脂蛋白(a)和去唾液酸脂蛋白(a)代谢影响的对比分析

分析多糖和姜黄素对脂蛋白（ａ）和去唾液酸脂蛋白（ａ）和去唾液酸脂蛋白（ａ）代谢的影响,从刺猥腋下静脉注入甘露聚糖、壳聚糖、α－酸性糖蛋白和姜黄素,２ｍｉｎ后注射＾１２５Ｉ－脂蛋白（ａ）或＾１２５Ｉ－去唾液酸脂蛋白（ａ）,１ｈ后处死动物,测定血、肝、肾、脾、胆汁和肾上腺的同位素含量。结果发现,脂蛋白（ａ）去唾液酸后能大量进入肝脏,加速在体内的分解代谢,使血中浓度迅速降低。α－酸性糖蛋白抑制组织对脂蛋白（ａ）和去唾液酸脂蛋白（ａ）的摄入,使血中脂蛋白（ａ）和去唾液酸脂蛋白（ａ）含量显著增高。壳聚糖和姜黄素增加肝脏和肾上腺对脂蛋白（ａ）的摄取,使血中脂蛋白（ａ）含量略降低,但对去唾液酸脂蛋白（ａ）代谢无明显影响。甘露聚糖增加脾脏对脂蛋白（ａ）的摄取,减少胆囊中脂蛋白（ａ）含量,但增加肾脏和胆囊对去唾液酸脂蛋白（ａ）的     

Regenerative phenotype in mice with a point mutation in transforming growth factor beta type I receptor (TGFBR1)

Regeneration of peripheral differentiated tissue in mammals is rare, and regulators of this process are largely unknown. We carried out a forward genetic screen in mice using N-ethyl-N-nitrosourea mutagenesis to identify genetic mutations that affect regenerative healing in vivo. More than 400 pedigrees were screened for closure of a through-and-through punch wound in the mouse ear. This led to the identification of a single pedigree with a heritable, fast, and regenerative wound-healing phenotype. Within 5 wk after ear-punch, a threefold decrease in the diameter of the wound was observed in the mutant mice compared with the wild-type mice. At 22 wk, new cartilage, hair follicles, and sebaceous glands were observed in the newly generated tissue. This trait was mapped to a point mutation in a receptor for TGF-β, TGFBR1. Mouse embryonic fibroblasts from the affected mice had increased expression of a subset of TGF-β target genes, suggesting that the mutation caused partial activation of the receptor. Further, bone marrow stromal cells from the mutant mice more readily differentiated to chondrogenic precursors, providing a plausible explanation for the enhanced development of cartilage islands in the regenerated ears. This mutant mouse strain provides a unique model to further explore regeneration in mammals and, in particular, the role of TGFBR1 in chondrogenesis and regenerative wound healing.     

Malaria control by residual insecticide spraying in Chingola and Chililabombwe,Copperbelt Province,Zambia

Malaria is endemic in the whole of Zambia and is the leading cause of morbidity and mortality. Prior to 1980, effective malaria control was achieved in the northern mining towns of Chingola and Chililabombwe by means of annual residual spraying programmes. In the 1970s, incidence rates were as low as 20/1000 p.a., but by 2000 had increased to 68/1000 p.a. in Chingola and to 158/1000 p.a.in Chililabombwe. Konkola Copper Mines (KCM) initiated a malaria control programme in which all dwellings in the two towns and within a 10-km radius were sprayed with either dichlorodiphenyltrichloroethane or a synthetic pyrethroid (Icon by ZENECA or Deltamethrin by Aventis). Houses were sprayed in November and December 2000, at the start of the peak transmission period. There was a statistically significant reduction in malaria incidence recorded at KCM health facilities in the two towns, representing a protective incidence rate ratio of 0.65 (95% CI 0.44, 0.97) when comparing the post-spraying period with the corresponding period of the previous 2 years. This reduction followed a single round of house spraying during a year with higher rainfall than the preceding two and in an area where chloroquine was first-line treatment. This house-spraying programme is an example of private/public sector collaboration in malaria control.     

克山病病区粮喂饲大鼠组织维生素E和Se GSH—Px的测定分析

用克山病病区粮喂饲大鼠15周,其肝脏、心脏、胰腺、肾脏、脾脏及全血Se GSH-Px活性都明显低于非病区粮喂养的大鼠,骨骼肌Se GSH-Px活性亦有降低的趋势,但差异不显著。Vit.E测定的结果表明,用病区粮喂养的大鼠肝脏和血清中Vit.E的含量明显高于用非病区粮喂养的大鼠;肾脏、脾脏和胰腺中Vit.E的含量和非病区粮组大鼠相比,亦有增高的趋势,但没有统计学差异;唯独在心肌和骨骼肌中Vit.E的含量两组间基本相同,病区粮组无丝毫增多迹象。 病区粮喂养大鼠肝脏和血清中Vit.E含量明显增多是吸收增多的表现,是对体内低硒的代偿反应,说明病区粮喂养大鼠体内对Vit.E的需要量增加。Vit.E在体内变化不一致,说明各脏器对Vit.E的摄取能力存在着差异,由于心肌和骨骼肌摄入Vit.E的能力较弱,尤易发生Vit.E相对不足的现象,成为克山病病变之主要靶器官。因此应重视硒和Vit.E联合缺乏在克山病发病中的作用。     

Synchronous occurrence of a hepatic myelolipoma and two hepatocellular carcinomas

Myelolipoma is a rare tumor composed of fat and bone marrow components, most of which are located in the adrenal gland. Myelolipoma in the liver is extremely rare. To date, only 10 cases have been reported in the English-language medical literature. In one of these cases, the hepatic myelolipoma was found within a hepatocellular carcinoma(HCC). In the present study, we report the first case of the synchronous occurrence of hepatic myelolipoma and HCCs in different liver sections of one patient, a 26-year-old female who was admitted to our hospital because of a 4-d history of upper abdominal pain. The unenhanced computed tomography(CT) images showed a well-defined lowdensity mass with adipose components in the right liver lobe, 4.2 cm × 4.1 cm in size. Two inhomogeneous low-density masses were found in the left liver lobe, 8.6 cm × 7.7 cm and 2.6 cm × 2.6 cm in size. The masses in both the right and left liver lobes were heterogeneously enhanced in the contrast-enhanced CT images. Based on the results of the imaging examination, the mass in the right liver lobe was preliminarily considered to be a hamartoma, and the two masses in the left liver were preliminarily considered to be HCCs. We performed a right hepatectomy, a left hepatic lobectomy, and a cholecystectomy. Microscopic and immunohistochemical results revealed that the tumor in the right liver lobe was a hepatic myelolipoma, and that the two tumors in the left liver lobe were HCCs.     

Latent autoimmune diabetes mellitus in adult humans with non-insulin-dependent diabetes: isPsammomys obesus a suitable animal model?

Recent data suggest that in a proportion of NIDDM patients there is a slowly evolving insulitis which results in a latent autoimmune diabetes leading to full insulin-dependence. Many animal models exist of NIDDM but none have reported the spontaneous existence of a similar phenomenon. We have re-examined the histology of pancreata from a few Psammomys obesus who had become insulin-dependent in the late stages of NIDDM. We report here the unexpected finding of the presence of insulitis in these animals and suggest that they could be a model for the clinical observation of latent IDDM in NIDDM patients.     

Cytokeratms and carcinoembryonic antigen in diagnosis, staging and prognosis of colorectal adenocarcinoma

AIM: To evaluate the serum levels of cytokeratins and carcinoembryonic antigen (CEA) in diagnosis, staging and prognosis of patients with colorectal adenocarcinoma. METHODS: The sample consisted of 169 patients. One hundred blood donors formed the control group. Radical surgery was performed on 120 patients, with an average follow-up duration of 22.3 mo. Relapses occurred in 23 individuals after an average of 18.09 mo. CEA was assayed via the Delfia method with a limit of 5 ng/mL Cytokeratins were assayed via the LIA-mat TPA-M Prolifigen method with a limit of 72 U/L. RESULTS: In the diagnosis of patients with colorectal adenocarcinoma, CEA showed a sensitivity of 56%, a specificity of 95%, a positive predictive value of 94%, a negative predictive value of 50% and an accuracy of 76.8%. TPA-M had a sensitivity of 70%, a specificity of 96%, a positive predictive value of 97%, a negative predictive value of 66% and an accuracy of 93.6%. The elevation of one of the markers was shown to have a sensitivity of 76.9%, a specificity of 91%, a positive predictive value of 93.5%, a negative predictive value of 70% and an accuracy of 83.6%. There was no variation in the levels of the markers according to the degree of cell differentiation while there was an elevation in their concentrations in accordance with the increase in neoplastic dissemination. There was a statistically significant difference between the patients with stage IV lesions and those with stages I, II and III tumors. With regard to CEA, the average level was 14.2 ng/mL in patients with stage I lesions, 8.5 ng/mL in patients with stage II lesions, 8.0 ng/mL in patients with stage III lesions and 87.7 ng/mL in patients with stage IV lesions. In relation to TPA-M, the levels were 153.1 U/L in patients with stage I tumors, 106.5 U/L in patients with stage II tumors, 136.3 U/L in patients with stage III tumors and 464.3 U/L in patients with stage IV tumors. There was a statistical difference in patients with a high CEA level in relation to a shorter survival (P<0.05). However, there was no correlation between patients with high TPA-M levels and prognostic indices of patients undergoing radical surgery. CONCLUSION: Cytokeratins demonstrate a greater sensitivity than CEA in the diagnosis of colorectal adenocarcinoma. There is an increase in the sensitivity of the markers with tumor dissemination. Cytokeratins cannot identify the worse prognosis in patients undergoing radical surgery, Cytokeratins constitute an advance in the direction of a perfect tumor marker in the treatment of patients with colorectal cancer.     

Cytokeratins and carcinoembryonic antigen in diagnosis, staging and prognosis of colorectal adenocarcinoma

AIM: To evaluate the serum levels of cytokeratins and carcinoembryonic antigen (CEA) in diagnosis, staging and prognosis of patients with colorectal adenocarcinoma.METHODS: The sample consisted of 169 patients. One hundred blood donors formed the control group. Radical surgery was performed on 120 patients, with an average follow-up duration of 22.3mo. Relapses occurred in 23individuals after an average of 18.09mo. CEA was assayed via the Delfia method with a limit of 5ng/mL. Cytokeratins were assayed via the LIA-mat TPA-M Prolifigen method with a limit of 72U/L. RESULTS: In the diagnosis of patients with colorectal adenocarcinoma, CEA showed a sensitivity of 56%, a specificity of 95%, a positive predictive value of 94%, a negative predictive value of 50% and an accuracy of 76.8%. TPA-M had a sensitivity of 70%, a specificity of 96%, a positive predictive value of 97%, a negative predictive value of 66% and an accuracy of 93.6%. The elevation of one of the markers was shown to have a sensitivity of 76.9%, a specificity of 91%, a positive predictive value of 93.5%, a negative predictive value of 70% and an accuracy of 83.6%. There was no variation in the levels of the markers according to the degree of cell differentiation while there was an elevation in their concentrations in accordance with the increase in neoplastic dissemination. There was a statistically significant difference between the patients with stage Ⅳ lesions and those with stages Ⅰ, Ⅱ and Ⅲ tumors.With regard to CEA, the average level was 14.2ng/mL in patients with stage Ⅰ lesions, 8.5ng/mL in patients with stage Ⅱ lesions, 8.0ng/mL in patients with stage Ⅲ lesions and 87.7ng/mL in patients with stage Ⅳ lesions. In relation to TPA-M, the levels were 153.1U/L in patients with stage Ⅰ tumors, 106.5U/L in patients with stage Ⅱ tumors, 136.3U/L in patients with stage Ⅲ tumors and 464.3U/L in patients with stage Ⅳ tumors. There was a statistical difference in patients with a high CEA level in relation to a shorter survival (P&lt;0.05). However, there was no correlation between patients with high TPA-M levels and prognostic indices of patients undergoing radical surgery.CONCLUSION: Cytokeratins demonstrate a greater sensitivity than CEA in the diagnosis of colorectal adenocarcinoma. There is an increase in the sensitivity of the markers with tumor dissemination.Cytokeratins cannot identify the worse prognosis in patients undergoing radical surgery.Cytokeratins constitute an advance in the direction of a perfect tumor marker in the treatment of patients with colorectal cancer.     

Collaborative study to establish the first international standard for quantitation of anti-HPA-1a

BACKGROUND AND OBJECTIVES: This report describes the production of a freeze-dried preparation of pooled human plasma, containing immunoglobulin G (IgG) antibodies against the human platelet antigen 1a (HPA-1a). The material, coded 03/152, is proposed as an International Standard containing 100 arbitrary units of anti-HPA-1a for use in quantitative assays to determine the anti-HPA-1a activity in clinical samples. MATERIALS AND METHODS: Plasma samples containing potent anti-HPA-1a were pooled and freeze dried in 1-ml ampoules. In addition, three individual plasma samples were selected which had varying levels of anti-HPA-1a activity. The anti-HPA-1a activity of these three samples was determined by using a variety of quantitative assays with the proposed standard as a reference. RESULTS: An international collaborative study, which was part of the 2004 ISBT Platelet Immunology Workshop, involved 39 laboratories in 24 countries and showed that the anti-HPA-1a activity in three test samples could be reliably determined by using the proposed standard. CONCLUSIONS: Laboratories can use this standard to measure the anti-HPA-1a activity in patient's samples. Further studies are required to determine the relationship between anti-HPA-1a activity and clinical outcome in patients with neonatal alloimmune thrombocytopenia (NAIT).     

Sténose de l’artère rénale à distance d’une dénervation rénale pour HTA résistante

The onset of renal artery stenosis following a renal denervation is rare and occurs in the first few months after renal denervation. We report the onset of renal artery stenosis a long time after the renal denervation for resistant hypertension. This is a 74 year-old patient who stopped smoking in 1980 and who was treated for dyslipidemia with a revascularized coronary artery disease in 2011, a well-stabilized peripheral arterial disease since 2001, a stable asymptomatic carotid atheroma and a good kidney function. His hypertension known since 1995 became resistant. After the control of renal arteries by angio-CT scan, he had a renal denervation in October 2012. His blood pressure decreased 3 months later confirmed by self-blood pressure monitoring (SBPM) and ambulatory blood pressure monitoring (ABPM) with a CT scan with a non-significant renal artery stenosis in January 2014. He remained normotensive under treatment until July 2015 but his hypertension became uncontrolled at the end of 2015 then resistant and severe confirmed by SBPM in April 2017, despite a 5-drug antihypertensive treatment associated to atorvastatin and clopidogrel confirmed by SBPM in April 2017. A left post-ostial renal artery stenosis with decrease in size of left kidney and cortex as compared to 2011 was detected at CT and treated by angioplasty. It was associated with a rapid decrease in blood pressure but unfortunately a new increase related to a restenosis occurred at the end of 2017, which justified a new angioplasty. Discussion about the etiology and the management of this renal post-denervation late stenosis.     

Apoptosis: a basic biological phenomenon with wide-ranging implications in human disease

Apoptosis is a highly regulated process of cell deletion and plays a fundamental role in the maintenance of tissue homeostasis in the adult organism. Numerous studies in recent years have revealed that apoptosis is a constitutive suicide programme expressed in most, if not all cells, and can be triggered by a variety of extrinsic and intrinsic signals. Many human diseases can be attributed directly or indirectly to a derangement of apoptosis, resulting in either cell accumulation, in which cell eradication or cell turnover is impaired, or cell loss, in which the apoptotic programme is inadvertently triggered. In addition, defective macrophage engulfment and degradation of cell corpses may also contribute to a dysregulation of tissue homeostasis. An increased understanding of the signalling pathways that govern the execution of apoptosis and the subsequent clearance of dying cells may thus yield novel targets for therapeutic intervention in a wide range of human maladies.     

Difference in the Burst Patterns of Digastric and Mylohyoid Activities during Feeding in the Freely Behaving Rabbit

Burst patterns in the digastric, mylohyoid, and masseter muscles and the resultant jaw movement orbits during chewing and swallowing were investigated in the freely behaving rabbit. Activities in the posterior mylohyoid fibers consisted of two continuous bursts. Peaks in the first burst of the posterior fibers occurred in the middle part of opening and preceded the digastric burst. Peaks in the second burst occurred in the final part of opening and coincided with those in the working side of the digastric burst. After removal of the bilateral digastric muscles, the gape size during chewing was largely reduced in the final part of opening and in the early part of closing. The results suggest that (a) the digastric may have a role in opening the mandible widely beyond the rest position but may not have a major role in the control of the horizontal (mediolateral) jaw movement, (b) the posterior mylohyoid fibers may have a function as an elevator of the tongue in the early part of opening, and (c) the posterior mylohyoid fibers may have a function as a depressor of the jaw in the late part of opening. Electromyographic burst in the mylohyoid muscle began with marked activity in the mid-closing phase. The results support a role for the mylohyoid muscle as a leading muscle of swallowing. Swallowing events in the rabbit are easily distinguished from the activities of the mylohyoid muscle and the thyrohyoid muscle.     

Lipoprotein(a): An underrecognized genetic risk factor for malignant coronary artery disease in young Indians

Malignant coronary artery disease (CAD) refers to a severe and extensive atherosclerotic process involving multiple coronary arteries in young individuals (aged <45 years in men and <50 years in women) with a low or no burden of established risk factors. Indians, in general, develop acute myocardial infarction (AMI) about 10 years earlier; AMI rates are threefold to fivefold higher in young Indians than in other populations. Although established CAD risk factors have a predictive value, they do not fully account for the excessive burden of CAD in young Indians. Lipoprotein(a) (Lp(a)) is increasingly recognized as the strongest known genetic risk factor for premature CAD, with high levels observed in Indians with malignant CAD. High Lp(a) levels confer a twofold to threefold risk of CAD—a risk similar to that of established risk factors, including diabetes. South Asians have the second highest Lp(a) levels and the highest risk of AMI from the elevated levels, more than double the risk observed in people of European descent. Approximately 25% of Indians and other South Asians have elevated Lp(a) levels (≥50 mg/dl), rendering Lp(a) a risk factor of great importance, similar to or surpassing diabetes. Lp(a) measurement is ready for clinical use and should be an essential part of all CAD research in Indians.     

Effect of age on lipid peroxidation in a short-lived species of reptile, Calotes versicolor

The lipid peroxidation potential, measured as a thiobarbituric acid-reactive substance (TBA-RS) increased with advancing age in liver, brain and kidney of a short-lived species of reptile, Calotes versicolor. The same parameter did not show a significant change in an ageing heart. The pattern of age changes in lipid peroxidation potential in this species shows similarity with the findings in a majority of mammalian species. While suggesting a commonality in a basic mechanism of ageing between reptiles and mammals, the results also partially support the free radical theory of ageing.