A region-matching method for pulse transit time estimation: potential for improving the accuracy in determining carotid femoral pulse wave velocity

Carotid femoral pulse wave velocity (cfPWV) is the 'gold standard' for assessment of arterial stiffness. The reliability of cfPWV measurement depends on the estimation of pulse transit time (PTT). This study aimed to validate a region-matching method for determining PTT and cfPWV against the existing 'foot-to-foot' methods. A cohort of 81 subjects (33 males and 48 females) aged 25-80 (45.1±15.7 years) were studied. PTTs were estimated by the region matching and 'foot-to-foot' methods ('diastole minimum', 'maximum first derivative', 'maximum second derivative' and 'tangent intersection' methods) with manual identification as the reference method and were subsequently used to calculate cfPWV. In a subgroup of 30 individuals, the measurements were repeated after 1 h. There were excellent correlations between cfPWV obtained by the reference method and all the estimated methods (r>0.9, P<0.001 for all), except the diastole minimum method (r=0.793, P<0.001). The region-matching method yielded cfPWV with a better accuracy (mean difference=-0.161 m s(-1), limits of agreement: -0.79 to 0.46 m s(-1)) and repeatability (mean difference=-0.228 m s(-1), intraclass correlation coefficient=0.957) comparing with the 'foot-to-foot' methods. These results demonstrate that the proposed region-matching method is more accurate and suitable for PTT estimation and cfPWV measurement.

Pronounced climatic variations in Alaska during the last two millennia

Paired oxygen-isotopic analyses of abiotic carbonate and benthic-ostracode shells from lake sediments provide a continuous quantitative record of growing-season temperature for the past 2000 years in the northwestern foothills of the Alaska Range. This record reveals three time intervals of comparable warmth: anno Domini (A.D.) 0-300, 850-1200, and post-1800, the latter two of which correspond to the Medieval Climatic Anomaly and climatic amelioration after the end of the Little Ice Age. The Little Ice Age culminated at A.D. 1700, when the climate was approximately 1.7 degrees C colder than at present. A marked climatic cooling also occurred around A.D. 600, coinciding with extensive glacial advances in Alaska. Comparisons of this temperature record with ostracode trace-element ratios (Mg/Ca, Sr/Ca) further suggest that colder periods were wetter and vice versa during the past 2000 years.

[Long-term clinical observation after repair of ruptured Achilles tendon (with 62 cases report)]

OBJECTIVE

To investigate the clinical result and influence factors of prognosis after repair of ruptured Achilles tendon with operative treatment.

METHODS

From 1961 to 1994, 62 cases with ruptured Achilles tendon were treated operatively. Among them, "8"-shaped suture was used in 8 cases, aponeurosis flap repair in 30 cases, transfer repair of tendon of peroneus longus muscle in 2 cases, reverse "V-Y" shaped tendon plastic operation in 10 cases, and mattress suture of opposite ends in 12 cases.

RESULTS

Followed up 3 to 33 years, there was excellent in 40 cases, better in 13 cases, moderate in 6 cases, poor in 3 cases, 85.5% in excellent rate. Postoperative infection and re-rupture were occurred in 6 cases respectively.

CONCLUSION

Different operative procedures are adopted to achieve better long-term clinical result according to the injury types.

Distribution of SIV in lymph nodes of serially sacrificed rhesus monkeys

Rhesus monkeys were inoculated with SIVDeltaB670 and sacrificed 2, 4, 8, and 24 weeks after inoculation or when moribund. Two monkeys predicted to have a rapid disease course and two predicted to have a slower disease course were sacrificed at each time point. Lymph nodes were studied by histopathology, immunohistochemistry, in situ hybridization, electron microscopy, flow cytometry for lymphocyte subsets, and mitogen responsiveness. A greater selective decrease in peripheral CD4+CD29+ (helper-inducer/memory) T cells occurred in monkeys with high antigenemia. Although the percentage of CD8+ lymphocytes was increased and the CD4+/CD8+ ratio decreased in all infected groups, there were no consistent differences between monkeys with high or low antigenemia in lymph node lymphocyte subsets. Blastogenic responses of lymph node lymphocytes to PHA, ConA, or PWM were not significantly altered in infected monkeys. A reticular pattern typical of antigen deposition within germinal center follicular dendritic cells was seen in three monkeys with atrophic lymph nodes, high serum antigenemia, and a low percentage of circulating CD4+/CD29+ cells. More individually stained cells were in monkeys with high serum antigen and in moribund animals. By in situ hybridization, most monkeys had signal in a reticular pattern of germinal centers. Animals with higher levels of serum antigenemia tended to have more infected cells and a more intense signal. Extracellular virions were found between the FDC foot processes in the germinal centers of lymph nodes. Disease course was already established 2 weeks after inoculation.

Lentivirus-induced pulmonary lesions in rhesus monkeys (Macaca mulatta) infected with simian immunodeficiency virus

Necropsy reports from 28 rhesus monkeys that had been experimentally infected with simian immunodeficiency virus (SIV) and that were free of cytomegalovirus were reviewed. Lung sections from 24 of these monkeys that had no etiologic agent other than SIV detected in the lung were studied in detail by histopathologic, immunohistochemical, and electron microscopic examination and by in situ hybridization. Fourteen of the monkeys were part of a serial euthanasia study, while others were euthanatized after they became moribund. The following lesions were detected: perivascular inflammation, vasculitis, interstitial pneumonia, syncytial cells, hemorrhage, fibrin exudation, and pleural fibrosis. Perivascular inflammation was the most frequent lesion and occurred as early as 2 weeks after inoculation. Severe pneumonia and numerous syncytial cells were seen only in animals euthanatized because they had become moribund. The lesions appeared to be directly due to SIV infection. SIV antigens, RNA, and virions were detected in syncytial cells and macrophages by immunohistochemical examination, in situ hybridization, and transmission electron microscopic examination, respectively. The amount of virus present was correlated with the severity of the lesions. The SIV-induced lesions were different from those of the lymphocytic interstitial pneumonia, which occurs in human immunodeficiency virus-infected children and in ovine lentivirus-infected sheep and goats.

Liver disease in rhesus monkeys infected with simian immunodeficiency virus

Rhesus monkeys infected with simian immunodeficiency virus (SIV) develop a syndrome very similar to patients with acquired immune deficiency (AIDS), including liver disease. This prospective study was undertaken to define the pathology, course, and pathogenesis of liver disease in 20 rhesus monkeys (Macaca mulatta) after intravenous inoculation with the standardized isolate SIV/DeltaB670. Tissue samples from liver and gallbladder between 2 and 24 weeks after inoculation were examined histologically and immunohistochemically for SIV gag protein p26, and by in situ hybridization with an SIV riboprobe. Histologically there was infiltration of portal tracts and around hepatic veins and venules by mononuclear inflammatory cells, focal bile duct damage, proliferation of bile ductules, and focal lobular inflammation as early as 2 weeks after infection. The severity and extent of these lesions were graded semiquantitatively and showed that bile duct damage and hepatic venulitis were the most significant changes. Simian immunodeficiency virus gag protein p26 and SIV RNA were detected in scattered mononuclear cells in portal tracts and sinusoids, but not in hepatocytes or bile duct epithelial cells. The data indicate that the liver is involved early during the course of SIV infection, followed by persistent changes until the terminal stage of the disease. Our findings suggest that the liver damage in SIV-infected rhesus monkeys is similar to the changes observed previously in AIDS patients.

Thymus in simian immunodeficiency virus-infected rhesus monkeys

The thymuses from 20 simian immunodeficiency virus (SIV)-infected and 4 uninfected rhesus monkeys were examined at intervals after infection to determine whether there were specific SIV-induced lesions, to document the serial distribution of SIV antigens, mRNA, and DNA, to quantitate the number of infected cells, and to correlate thymic changes with other parameters of infection. The following techniques were used: gross pathology, histopathology, immunohistochemistry, electron microscopy, in situ hybridization, polymerase chain reaction, and limiting dilution culture. Thymic involution due to loss of lymphocytes was apparent 8 weeks after inoculation. No epithelial damage or loss of Hassall's corpuscles was observed. Culture was the most sensitive technique for detecting SIV, being positive in 19 of 20 inoculated monkeys. The polymerase chain reaction was negative in one thymus that was positive at a low level by culture. In situ hybridization was positive in 14 of 19 thymuses examined, with a few macrophages in the cortex having a strong signal and numerous lymphocytes in the medulla having a weak signal. Mature viral particles and viral budding could not be demonstrated by electron microscopy. The number of cells positive for viral RNA by in situ hybridization correlated with the level of serum antigenemia. These observations suggest that thymic macrophages and lymphocytes are infected with SIV within 2 weeks after inoculation. SIV apparently directly causes loss of thymic lymphocytes and immunodeficiency without infecting or damaging the thymic epithelium. No specific SIV-induced lesions were recognized. The number of cells in the thymic medulla expressing SIV RNA correlates with the level of serum antigen, which has been previously shown to be correlated with disease progression.

Serial pathogenesis study of SIV brain infection

A serial study of early SIV brain infection revealed initial involvement of leptomeninges, followed by perivascular infection of brain parenchyma. Severity of SIV encephalitis correlated with severity of systemic disease rather than with length of infection. Diffuse white matter disease was not observed, and there was little evidence of SIV infection of brain endothelial cells. SIV infection of leptomeninges is separate from infection of the brain, which appears to be due to transvascular spread of infected monocytes/macrophages.

Recurrent senescence in axenic cultures of Physarum polycephalum

When subcultures of the aux-2 and aux-4 strains of Physarum polycephalum, which had been grown for more than four years in axenic shake culture, were transferred to non-axenic surface culture they displayed progressively shorter lifespans (older axenic surface cultures yield shorter lived non-axenic cultures). Similar subcultures transferred to axenic agar medium also underwent senescent-like events. These subcultures, after a period of vigorous growth, displayed a slower growth rate, reduced cytoplasmic streaming, loss of yellow pigment, and eventually they fragmented into a number of small spherical structures with the concomitant lysis of most of the plasmodium. In non-axenic culture these structures quickly degenerated (and disappeared from the culture); however, in axenic culture they revived and after several days produced new vigorous plasmodia. Following a period of vigorous growth the plasmodium again underwent senescent-like events. This cycle of senescence and growth was repeated a number of times before death finally occurred.