[Progress in Application of Measuring Skeleton by CT in Forensic Anthropology Research]

Individual identification by measuring the human skeleton is an important research in the field of forensic anthropology. Computed tomography （CT） technology can provide high-resolution image of skeleton. Skeleton image can be reformed by software in the post-processing workstation. Different skeleton measurement indexes of anthropology, such as diameter, angle, area and volume, can be measured on section and reformative images. Measurement process is barely affected by human factors. This paper reviews the literatures at home and abroad about the application of measuring skeleton by CT in forensic anthropology research for individual identification in four aspects, including sex determination, height infer, facial soft tissue thickness measurement and age estimation. The major technology and the application of CT in forensic anthropology research are compared and discussed, respectively.

Blood pressure variability and organ damage

1. Blood pressure variability (BPV) is expressed as the standard deviation of the average blood pressure (BP). Blood pressure variability is increased in hypertensive patients and animals. However, BPV is not necessarily related to the BP level. 2. For nearly any level of 24 h mean BP, hypertensive patients in whom the BPV is low have a lower prevalence and severity of organ damage than patients in whom the 24 h BPV is high. This observation has been confirmed further in spontaneously hypertensive rats with direct pathological analysis for organ damage. 3. In sinoaortic-denervated (SAD) rats, 24 h average BP is normal and BPV is markedly increased. Myocardial damage, renal lesions and vascular remodelling are seen in these animals 4 weeks after SAD. 4. Haemodynamic effects and activation of the renin- angiotensin system are hypothesized to contribute to organ damage induced by increased BPV. 5. Blood pressure variability is of potential importance in antihypertensive therapy.

Effects of six antihypertensive drugs on blood pressure and hypothalamic GABA content in spontaneously hypertensive rats

In order to investigate the effects of antihypertensive drugs on blood pressure and gamma-amino butyric acid (GABA) content in the hypothalamus and the possible relationship between blood pressure decrease and GABA content changes, blood pressure and GABA contents after chronic (20 weeks) treatments of nitrendipine, atenolol, captopril, hydrochlorothiazide, dihydralazine and prazosin were studied in spontaneously-hypertensive rats (SHR). The acute and subacute (1 week) effects of nitrendipine on GABA contents was also observed in SHR. It was found that 20 week treatments with six different antihypertensive agents produced a decrease in systolic blood pressure and an increase in GABA content. The blood pressure level was significantly correlated with GABA content in the hypothalamus, but not with that in the cortex. Acute treatment with a single dose of nitrendipine, did not alter GABA content. Bicuculline, a GABA receptor antagonist, did not attenuate the hypotensive effect of nitrendipine. In conclusion, chronic treatments by different antihypertensive agents produced an increase of hypothalamic GABA content and a decrease of blood pressure. The increase of GABA content induced by nitrendipine seems likely to be secondary to blood pressure decrease.

Blood pressure variability is increased in genetic hypertension and L-NAME -induced hypertension

AIM

To examine whether the blood pressure variability (BPV) is increased in spontaneously hypertensive rats (SHR) and L-NAME-induced hypertensive rats (NHR).

METHODS

BPV was recorded with continuous hemodynamic monitoring in conscious un restrained rats. Time course of L-NAME-induced hypertension was measured by the tail-cuff method. Plasma NO concentration was determined by the method of nitric acid reductase.

RESULTS

In both SHR and NHR, systolic and diastolic BPV were significantly increased when compared with their respective controls. In S HR, in crease in diastolic BPV was predominant, whereas in NHR, increase in systolic BP V was predominant. Moreover, increase in systolic BPV in NHR (102 %) was obviously higher than that in SHR (28 %). Chronic administration of L-NAME 1 g/L in drink ing water caused a progressive increase in arterial blood pressure in rats. All rats were hypertensive at 4 weeks after treatment. Plasma NO level was decreased in NHR.

CONCLUSION

Increased BPV is a general phenomenon in hypertension. NO is involved in the regulation of BPV.

Arterial remodeling in chronic sinoaortic-denervated rats

The spontaneous variation of blood pressure is defined as "blood pressure variability" (BPV). The chronic sinoaortic-denervated (SAD) rat is a model of high BPV without sustained hypertension. Little is known about vascular remodeling in this model. In the present study, we examined blood pressure, vascular remodeling, and aortic angiotensin II concentration in chronic SAD rats in separate experiments. In experiment 1, intra-arterial blood pressure was continuously recorded in conscious unrestrained rats. The 16-week SAD rats had a significant increase in BPV and no change in the mean level of blood pressure over a 24-h period. In experiment 2, we measured structural changes of seven kinds of arteries by histologic method and computer image analysis and functional changes of thoracic aortas by isolated artery preparation. Structural remodeling after 16-week sinoaortic denervation was characterized by increase in wall thickness, wall area, and ratio of wall thickness to internal diameter, with different changes in internal diameter and external diameter in different arteries, indicating that arterial structural remodeling expresses itself mainly as vascular growth. This vascular growth might be caused by medial smooth muscle cell growth and collagen accumulation. Aortic contraction induced by norepinephrine was potentiated, whereas aortic relaxation induced by acetylcholine was attenuated after sinoaortic denervation. In experiment 3, plasma and aortic angiotensin II concentrations were determined by radioimmunoassay. The former remained unchanged, whereas the latter was significantly increased in 10-week SAD rats. It is concluded that in rats chronic sinoaortic denervation can produce vascular remodeling that might be related to increased BPV and an activated tissue renin-angiotensin system.

Hemodynamic responses to endothelin-1 and endothelin antagonists microinjected into the nucleus tractus solitarius in rats

The role of endothelin-1 (ET-1) within the nucleus tractus solitarius (NTS) in central cardiovascular control was investigated by local microinjections of ET-1 and ET-receptor antagonists. In urethane-anesthetized Sprague-Dawley rats, a unilateral microinjection of ET-1 (1.0, 3.3, and 10.0 pmol) into the NTS significantly increased arterial pressure, left ventricular systolic pressure, and dP/dt(max) in a dose-dependent manner, and slightly decreased heart rate in a dose-independent manner. The pressor effect lasted >90 min. In normotensive rats, neither PD147953, a selective ETA-receptor antagonist, nor PD142893, a mixed ETA- and ETB-receptor antagonist, microinjected into the NTS elicited any changes in arterial pressure or heart rate. The pressor and bradycardic effects evoked by microinjection of ET-1 into the NTS could be blocked by local pretreatment with PD147953 and completely eliminated by intravenous pretreatment with the ganglionic blocker hexamethonium. The arterial baroreflex sensitivity was almost totally suppressed by microinjection of ET-1 (3.3 pmol) in alpha-chloralose-anesthetized Sprague-Dawley rats. A similar pattern of changes in the hemodynamic variables was elicited by microinjection of ET-1 (3.3 pmol) into the NTS in spontaneously hypertensive rats (SHRs) compared with Wistar-Kyoto (WKY) rats. In SHRs, microinjection of PD142893 did not elicit any changes in arterial pressure or heart rate. These results suggest that ET-1 modulates reflex control of hemodynamics by activation of autonomic nerve via ETA receptors in the NTS, and that the responsiveness of SHRs to ET-1 or PD142893 is similar to that of WKY rats.

[Antihypertensive effects of atenolol and nitrendipine alone or in combination on three hypertensive models of rats]

The antihypertensive effects of atenolol (Ate) or nitrendipine (Nit) alone or in combination (Ate+Nit) were studied in conscious experimental hypertensive rats. The hypotensive effects of single ig of Ate 20 + Nit 10 mg.kg-1 were rapid and persistent in spontaneously hypertensive rats (SHR). In renovascular hypertensive rats (RVHR) and DOCA-salt hypertensive rats (DHR), Ate+Nit (6 + 3, 20 + 10, 60 + 30 mg.kg-1) given ig once a day for 10 d reduced the blood pressure in a dose-dependent manner. But Ate 20 mg.kg-1 or Nit 10 mg.kg-1 alone given ig once a day for 10 d caused no obvious reduction in blood pressure in RVHR, DHR, and SHR q = 1.32. These results revealed that the synergy is present in the antihypertensive action of Ate+Nit.

[Inhibitory effects of neferine and tetrandrine on portal vein and papillary muscle in rats]

To determine the vascular selectivity, the inhibitory effects of verapamil (Ver), neferine (Nef), and tetrandrine (Tet) on the spontaneous contractile force of portal vein and contractile force of the paced papillary muscle of left ventricle were studied in Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). The vascular selectivity was expressed by the IC50 ratio (IC50 for papillary muscle/IC50 for portal vein). The results showed that the vascular selectivity values of Ver, Nef, and Tet were 1.15, 0.32, and 0.20, respectively in WKY and 0.80, 0.24, and 0.10, respectively in SHR. It is concluded that Nef and Tet, in contrast with Ver which is devoid of selectivity for either tissue, are more liable to inhibit the myocardium than the vascular smooth muscle. In addition, the IC50 value of Tet for inhibition of the portal vein in SHR was nearly 10-fold higher than that in WKY (237 and 27 mumol.L-1, respectively). This indicates that the response of portal vein to Tet is decreased in SHR.

[Effects of tetrandrine on hypertensive responses induced by electric stimulation and alpha-adrenoceptor agonists in pithed rats]

Tetrandrine (Tet) 5 mg.kg-1 i.v. inhibited the pressor action of norepinephrine (NE) release induced by electric stimulation (10 V, 0.5-16 Hz) of spinal cord T11-L2. However, Tet 5 mg.kg-1 ia did not obviously attenuate the hypertensive responses to NE 0.51-16.91 micrograms.kg-1 i.v., indicating that Tet did not affect the alpha 1-adrenoceptors-mediated vasoconstriction. Tet 5 mg.kg-1 ia decreased the pressor responses to NE 0.05 and 0.17 micrograms.kg-1 i.v. and markedly reduced the dose-dependent hypertensive responses to B-HT920 i.v., a selective alpha 2-adrenoceptor agonist, proving that Tet reduced alpha 2-adrenoceptors-mediated vasoconstriction.

[Effects of sulmazole on beating rate and cAMP levels in cultured cardiomyocytes]

The effect of sulmazole (Sul) on beating rate of cultured neonatal rat cardiomyocytes was similar to that of isoproterenol (Iso). They all produced a positive chronotropic action in a dose-dependent manner (Sul 1-100 mumol/L, Iso 1-300 nmol/L). Iso increased intracellular cAMP levels in a dose-dependent manner simultaneously, while Sul did not until toxic concentration (1 mmol/L) was given. With Sul 300 mumol/L the cAMP levels were not elevated significantly even when the positive chronotropic effect was maximal (5 min). The results indicate that cAMP is not important in mediating the positive chronotropic effect of Sul.

Prevalence of congenital cardiac anomalies at high altitude

The effect of high altitude on the prevalence of congenital heart disease was tested by examining 1,116 school children at four study sites in the People's Republic of China. Sites ranged in altitude from sea level to 4,500 m above sea level. Children were screened by physical examination, and an echocardiogram and electrocardiogram were performed on each child suspected of having a cardiac anomaly. A high prevalence of patent ductus arteriosus and atrial septal defect was found at the three high altitude sites and the effect of altitude was progressive. Both anomalies were postulated to be the result of the lower atmospheric oxygen tension present at high altitude. Failure of lower oxygen tension to constrict the ductus is thought to be the mechanism in patent ductus arteriosus. It is theorized that the persistence of high pulmonary vascular resistance and high right heart pressures at high altitude inhibits early closure of the foramen ovale. Subsequent growth may result in stretching of the fossa ovalis and incompetence of the flap and may produce an atrial septal defect. The high prevalence of atrial septal defect in tetralogy of Fallot is cited as a possible analogy because right ventricular pressure is high and right ventricular compliance is low from birth.