Palms of the past: can morphometric phytolith analysis inform deep time evolution and palaeoecology of Arecaceae?

BACKGROUND AND AIMS: Palm fossils are often used as evidence for warm and wet palaeoenvironments, reflecting the affinities of most modern palms. However, several extant palm lineages tolerate cool and/or arid climates, making a clear understanding of the taxonomic composition of ancient palm communities important for reliable palaeoenvironmental inference. However, taxonomically identifiable palm fossils are rare and often confined to specific facies. Although the resolution of taxonomic information they provide remains unclear, phytoliths (microscopic silica bodies) provide a possible solution because of their high preservation potential under conditions where other plant fossils are scarce. We thus evaluate the taxonomic and palaeoenvironmental utility of palm phytoliths. METHODS: We quantified phytolith morphology of 97 modern palm and other monocot species. Using this dataset, we tested the ability of five common discriminant methods to identify nine major palm clades. We then compiled a dataset of species' climate preferences and tested if they were correlated with phytolith morphology using a phylogenetic comparative approach. Finally, we reconstructed palm communities and palaeoenvironmental conditions at six fossil sites. KEY RESULTS: Best-performing models correctly identified phytoliths to their clade of origin only 59 % of the time. Although palms were generally distinguished from non-palms, few palm clades were highly distinct, and phytolith morphology was weakly correlated with species' environmental preferences. Reconstructions at all fossil sites suggested that palm communities were dominated by Trachycarpeae and Areceae, with warm, equable climates and high, potentially seasonal rainfall. However, fossil site reconstructions had high uncertainty and often conflicted with other climate proxies. CONCLUSIONS: While phytolith morphology provides some distinction among palm clades, caution is warranted. Unlike prior spatially restricted studies, our geographically and phylogenetically broad study indicates phytolith morphology may not reliably differentiate most palm taxa in deep time. Nevertheless, it reveals distinct clades, including some likely to be palaeoenvironmentally informative.

Prognostic impact of inter-metastatic heterogeneity of viable tumour cells in colorectal liver metastases.

BACKGROUND: Heterogenous response to neoadjuvant chemotherapy in patients with multiple colorectal liver metastases (CRLM) has been associated with an acquired resistance to systemic therapy. This study evaluated the occurrence of a heterogenous inter-metastatic tumour response with regards to the proportion of viable tumour cells, and its prognostic impact. METHODS: A retrospective cohort study was conducted, including all patients with CRLM surgically treated at Karolinska University Hospital, Stockholm, Sweden, from 2013 to 2018. Factors associated with the proportion of viable tumour cells and inter-metastatic heterogeneity were analysed with regression and survival analyses. RESULTS: Out of 640 surgically treated patients, 405 patients (1357 CRLM), received neoadjuvant chemotherapy. Multiple CRLM were present in 314 patients (78%), out of whom 72 patients (23%) presented with a heterogenous tumour response. The median overall survival (OS) for patients with a heterogenous inter-metastatic tumour response was 36 months, compared to 57 months for patients with a homogenous inter-metastatic tumour response (p < .001). Poor OS in patients receiving preoperative chemotherapy was significantly associated with a heterogenous inter-metastatic tumour response (hazard ratio (HR) 1.68 (1.02-2.78)), right-sided primary tumour (HR 2.01 (1.29-3.43)) and CRLM diameter >5 cm (HR 1.83 (1.06-3.17)). CONCLUSION: Outcome in patients with a heterogenous inter-metastatic tumour response, illustrated by the proportion of viable tumour cells, is inferior to that of patients with a homogenous response. These results suggest that heterogeneity in treatment response is an important marker of aggressive disease and could be of clinical value for decisions on post-operative therapy.

Treatment patterns and survival in patients with hepatocellular carcinoma in the Swedish national registry SweLiv.

BACKGROUND: Consistent data on clinical features, treatment modalities and long-term survival in patients with hepatocellular carcinoma (HCC) using nationwide quality registers are lacking. This study aimed to describe treatment patterns and survival outcomes in patients diagnosed with HCC using a national maintained database. METHODS: Characteristics and treatment patterns in patients diagnosed with HCC and registered in the national register of liver and bile duct tumours (SweLiv) between 2009 and 2016 were reviewed. Overall survival (OS) was estimated using Kaplan-Meier analysis and the log rank test to compare subgroups for clinical features, treatment modalities and outcomes according to the year of treatment. RESULTS: A total of 3376 patients with HCC were registered over 8 years, 246 (7·3 per cent) of whom underwent transplantation. Some 501 (14·8 per cent) and 390 patients (11·6 per cent) had resection and ablation as primary treatment. Transarterial chemoembolization and systemic sorafenib treatment were intended in 476 (14·1 per cent) and 426 patients (12·6 per cent) respectively; the remaining 1337 (39·6 per cent) were registered but referred for best supportive care (BSC). The 5-year survival rate was approximately 75 per cent in the transplantation group. Median OS was 4·6 (i.q.r. 2·0 to not reached) years after resection and 3·1 (2·3-6·7) years following ablation. In patients referred for palliative treatment, median survival was 1·4 (0·8-2·9), 0·5 (0·3-1·2) and 0·3 (0·1-1·0) years for the TACE, sorafenib and BSC groups respectively (P < 0·001). Median survival was 0·9 years for the total HCC cohort in 2009-2012, before publication of the Swedish national treatment programme, increasing to 1·4 years in 2013-2016 (P < 0·001). CONCLUSION: The survival outcomes reported were in line with previous results from smaller cohorts. The introduction of national guidelines may have contributed to improved survival among patients with HCC in Sweden.

ANTECEDENTES: Se carece datos consistentes acerca de las características clínicas, modalidades terapéuticas y supervivencia a largo plazo en pacientes con carcinoma hepatocelular (hepatocellular carcinoma, HCC) basados en registros de calidad de ámbito nacional. El objetivo de este estudio fue describir los patrones de tratamiento y los resultados de supervivencia en pacientes diagnosticados de HCC usando una base de datos nacional. MÉTODOS: Se revisaron las características de los pacientes y los patrones de tratamiento en pacientes con un diagnóstico de HCC incluidos en el registro nacional de tumores de hígado y vías biliares (SweLiv) entre 2009 y 2016. La supervivencia global (overall sirvival, OS) se analizó mediante el método de Kaplan-Meier y test de log-rank para la comparación de subgrupos según las características clínicas de los pacientes, las modalidades de tratamiento y los resultados en función del año de tratamiento. RESULTADOS: Durante un periodo de 7 años, se incluyeron en el registro un total de 3.076 pacientes con HCC, 246 de los cuales recibieron un trasplante (7,2%). Se practicó resección y ablación como tratamiento primerio en 501 (14,8%) y 390 (11,6%) pacientes, respectivamente. La quimioembolización (TACE) y el tratamiento sistémico con sorafenib se efectuó en 476 (14,1%) y 426 (12,6%) pacientes, respectivamente; los 1.337 pacientes restantes (40,0%) fueron incluidos en la base de datos pero se derivaron para recibir el mejor tratamiento de soporte. La tasa de supervivencia a los 5 años fue del 75% en el grupo trasplantado. La mediana de OS fue de 4,6 años (rango intercuartílico, interquartile range, IQR 2,0-no alcanzado) tras la resección y de 3,1 años (IQR 2,3-6,7) tras la ablación. En los pacientes derivados para tratamiento paliativo, la mediana de supervivencia fue de 1,4 años (IQR 0,8-2,9), 0,5 años (IQR 0,2-1,2) y 0,3 años (IQR 0,1-1,0) para los grupos de TACE, sorafenib y mejor tratamiento de soporte, respectivamente (P < 0,001). La mediana de supervivencia para toda la cohorte de HCC en 2009-2012 fue de 0,9 años antes de la publicación del programa de nacional de tratamiento sueco, aumentando a 1,4 años en 2013-2016 (P <0,001). CONCLUSIÓN: Los resultados de supervivencia referidos eran consistentes con resultados previos obtenidos en cohortes más pequeñas; la introducción de guías nacionales puede haber contribuido a mejorar la supervivencia de los pacientes con HCC en Suecia.

Selective intraoperative cholangiography and risk of bile duct injury during cholecystectomy.

BACKGROUND: Whether intraoperative cholangiography can prevent iatrogenic bile duct injury during cholecystectomy remains controversial. METHODS: Data from the national Swedish Registry for Gallstone Surgery, GallRiks (May 2005 to December 2010), were analysed for evidence of iatrogenic bile duct injury during cholecystectomy. Patient- and procedure-related risk factors for bile duct injury with a focus on the rate of intended intraoperative cholangiography were analysed using multivariable logistic regression. RESULTS: A total of 51 041 cholecystectomies and 747 bile duct injuries (1·5 per cent) were identified; 9008 patients (17·6 per cent) were diagnosed with acute cholecystitis. No preventive effect of intraoperative cholangiography was seen in uncomplicated gallstone disease (odds ratio (OR) 0·97, 95 per cent c.i. 0·74 to 1·25). Operating in the presence (OR 1·23, 1·03 to 1·47) or a history (OR 1·34, 1·10 to 1·64) of acute cholecystitis, and open surgery (OR 1·56, 1·26 to 1·94), were identified as significant risk factors for bile duct injury. The intention to perform intraoperative cholangiography was associated with a reduced risk of bile duct injury in patients with concurrent (OR 0·44, 0·30 to 0·63) or a history of (OR 0·59, 0·35 to 1·00) acute cholecystitis. CONCLUSION: Any proposed protective effect of intraoperative cholangiography was restricted to patients with (or a history of) acute cholecystitis.

Late Cretaceous origin of the rice tribe provides evidence for early diversification in Poaceae.

Rice and its relatives are a focal point in agricultural and evolutionary science, but a paucity of fossils has obscured their deep-time history. Previously described cuticles with silica bodies (phytoliths) from the Late Cretaceous period (67-65 Ma) of India indicate that, by the latest Cretaceous, the grass family (Poaceae) consisted of members of the modern subclades PACMAD (Panicoideae-Aristidoideae-Chloridoideae-Micrairoideae-Arundinoideae-Danthonioideae) and BEP (Bambusoideae-Ehrhartoideae-Pooideae), including a taxon with proposed affinities to Ehrhartoideae. Here we describe additional fossils and show that, based on phylogenetic analyses that combine molecular genetic data and epidermal and phytolith features across Poaceae, these can be assigned to the rice tribe, Oryzeae, of grass subfamily Ehrhartoideae. The new Oryzeae fossils suggest substantial diversification within Ehrhartoideae by the Late Cretaceous, pushing back the time of origin of Poaceae as a whole. These results, therefore, necessitate a re-evaluation of current models for grass evolution and palaeobiogeography.

Nationwide study of the treatment of common bile duct stones in Sweden between 1965 and 2009.

BACKGROUND: Treatment of common bile duct stones has changed. Open surgery has gradually been replaced by endoscopic and laparoscopic procedures. The aims of this study were to see how common bile duct stones have been treated in Sweden, to establish whether there were differences in morbidity and mortality between these approaches, and to identify factors influencing mortality. METHODS: All persons undergoing inpatient common bile duct exploration or endoscopic retrograde cholangiopancreatography (ERCP) during 1965-2009 in the Swedish Hospital Discharge Registry, but without a diagnosis of malignancy in the Swedish Cancer Registry, were included. The outcome death was identified by cross-linkage to the Causes of Death Registry. Registry data on possible risk factors for mortality were collected. RESULTS: A total of 126 885 procedures were performed in 110 119 patients. Open surgery was initially the only available method, but during the 1990s ERCP became predominant. Later, laparoscopic bile duct clearance became an established but uncommon method. A 90-day mortality rate of 0·2 per cent after open surgery, 0·8 per cent after ERCP, 0 per cent after laparoscopic exploration and 0·7 per cent after combined procedures was recorded. After adjustment for confounding, there was no difference in mortality between open surgery and ERCP. Biliary reintervention within 90 days was identified as a risk factor for death, whereas a concomitant diagnosis of pancreatitis reduced the risk. CONCLUSION: The laparoscopic technique had the lowest mortality and morbidity rates. After adjustment for confounding factors, there was no difference in mortality after open surgery and ERCP. The favourable outcome for laparoscopy may have been due to selection bias, owing to treatment of younger, healthier subjects with less severe disease.

Hydrogen bond dynamics probed with ultrafast infrared heterodyne-detected multidimensional vibrational stimulated echoes.

Hydrogen bond dynamics are explicated with exceptional detail using multidimensional infrared vibrational echo correlation spectroscopy with full phase information. Probing the hydroxyl stretch of methanol-OD oligomers in CCl4, the dynamics of the evolving hydrogen bonded network are measured with ultrashort (<50 fs) pulses. The data along with detailed model calculations demonstrate that vibrational relaxation leads to selective hydrogen bond breaking on the red side of the spectrum (strongest hydrogen bonds) and the production of singly hydrogen bonded photoproducts.

Long-term results from laparoscopic common bile duct exploration.

BACKGROUND: The aim of this study was to evaluate the long-term results after laparoscopic common bile duct exploration (LCBDE). METHODS: A retrospective review of 175 consecutive patients who underwent attempted LCBDE between 1992 and 1999 was conducted. Laparoscopic transcystic exploration was accomplished in 110 patients and laparoscopic choledochotomy in 52 patients. Conversion to an open common bile duct exploration was required for 13 patients (7.4%). Retained common bile duct stones occurred in eight patients (4.6%). The 30-day postoperative morbidity was 6.9%, and there was no 30-day mortality. All the patients (alive and localized) received a questionnaire evaluating long-term results. RESULTS: Of the 175 patients, 169 (4 unrelated deaths and 2 patients lost to follow-up evaluation) received and 152 (90%) returned the questionnaire. The follow-up period ranged from 6 to 72 months (median, 36 months). One patient developed recurrent common bile duct stones. There were no signs or evidence of common bile duct stricture in any patient. CONCLUSION: The LCBDE procedure can be performed without increased risk of late bile duct complications.

Charnley cups retained during revision of the femoral component: repeated clinical and radiographic observations of 49 cups for 7-15 years.

This article concerns 49 consecutive polyethylene cups retained in cemented first revisions of the femoral component and evaluated on several occasions 7-15 years after the index operation. At the last follow-up 5 cups were revised, 3 were radiographically loose, 1 was revised because of recurrent dislocation and 1 stable cup was revised because the surgeon wished to use a 28 mm head. Moreover, 1 unrevised cup was radiographically loose. This corresponded to a mechanical failure rate of 0.1 (5/49) and revision rate of 0.1 (4/49). 3 cups which were radiographically loose (100% radiolucency) had not been revised when the stem was exchanged. If these cups were excluded, the revision rate would have dropped to 0.02 (1/46) and the mechanical failure rate to 0.04 (2/46). This indicates the importance of careful preoperative radiographic evaluation on both AP and lateral views. Progression of radiolucent lines always occurred as an increase in extension from the periphery to the central region of the interface. In conclusion, Charnley cups with non-circumferential radiolucent lines and little, if any, wear can be retained without compromising the longevity of the implant. However, it should be stressed that this conclusion is based on a patient population in which four-fifths of the patients at the index operation were 65 years of age or older.

Cemented first-time revisions of the femoral component: prospective 7 to 13 years' follow-up using second-generation and third-generation technique.

In a prospective, consecutive study of first-time cemented femoral revisions, 109 hips were evaluated for a minimum of 7 years. There were 87 Charnley (18 standard, 69 long), 21 Spectron (3 standard, 18 long), and 1 Brunswick long-stem arthroplasties. There was an increased risk for rerevision in younger patients (P = .0001) and with use of standard stems (P = .002). Factors of importance for development of mechanical failure were younger age (P = .0001), presence of more pronounced bone defects (P < .005), use of standard stems (P < .0005), and presence of radiolucencies on the postoperative radiographs (Gruen zones 4 and 6) (P < .01). Our results confirm that cemented femoral revisions are a durable option in elderly patients, when improved cementing techniques and long-stem prostheses are used.

The structure and dynamics of worry: theory, measurement, and cross-national replications.

This article presents a comprehensive conceptualization of the structure of worry and the relation of worry to mental health and well-being. It is assumed that worries have two facets, namely, the object of a worry (e.g., self, close others, society, the world) and the domain of a worry (the field of life with which it is concerned). The object of a worry is presumed to be more important than its domain in determining the impact of worries on mental health. Only worries concerned with self and close others (micro worries) are expected to be related to poor mental health, whereas worries about society or the entire world (macro worries) are expected to be positively related to mental health. An instrument is introduced to study worries in accordance with the proposed structure. Its validity is tested by two confirmatory techniques (similarity structure analysis and confirmatory factor analysis) in samples from Israel, West Germany, and (the former) East Germany. Worry scores are also related to five mental health indicators. Results show that across samples micro and macro worries can validly be distinguished. Micro worries are strongly related to poor mental health, whereas macro worries are unrelated to mental health or relate marginally to positive well-being.

[Laparoscopy possible even in cholelithiasis. Results for 96 patients from three different hospitals are reviewed]. / Laparoskopi möjlig även vid koledokussten. Resultaten för 96 patienter från tre sjukhus redovisas.

At laparoscopic cholecystectomy, a procedure routinely used at Swedish surgery departments today, common bile duct stones are found to be present in 5-10 per cent of cases. During recent years, several alternative procedures have been evolved for the management of duct stones, such as operative or postoperative endoscopic sphincterolomy, or conversion to open surgery and choledochotomy. The article gives an account of laparoscopic treatment of common bile duct stones, and results obtained in 96 patients from three surgery departments in Sweden. Three different primary techniques were used: saline flushing via the cholangiography catheter, after intravenous injection of 1 mg of glucagon (in six cases of small stones); transcystic common duct exploration (TCDE), with cholodochoscopy and a Dermia basket (68 cases); and laparoscopic choledochotomy and choledochoscopy (22 cases). The success rate was 88 per cent (84/96), and mortality zero. In many cases the postoperative course was similar to that of patients undergoing laparoscopic cholecystectomy alone. We recommend TCDE in cases of common bile duct stones of no more than 8-9 mm in diameter, and where the cystic duct is large. Single-stage laparoscopic treatment of bile duct stones seems to be a safe and effective method of dealing with two problems in the same setting, and is an important alternative in the management of duct stones.

The effects of midazolam and ephedrine on post-exercise autonomic chronotropic control of the heart in normal subjects.

Benzodiazepines may induce hypotension by inhibiting the pressor response. Ephedrine has adrenergic effects on the circulation. After exercise, changes in cardiovascular control impair orthostatic tolerance. The impaired pressure response can be compensated for by chronotropic control of the heart. We studied the effect of midazolam and ephedrine on post-exercise cardiac autonomic chronotropic control in six 21-year-old female volunteers, who received single doses of 15 mg midazolam, 50 mg ephedrine, or placebo orally according to a placebo-controlled, double-blind, crossover design. After exercise, the subjects assumed the supine position for rest, then a -10 degrees head-down position followed by a 70 degrees head-up position. Power spectral analysis of heart rate variability for 7 min and steady-state brachial arterial blood pressure were measured in each position. After administration of midazolam, three subjects had an abnormal fall in their arterial blood pressure (with one presyncope) as a response to head-up tilt. Changes in heart rate variability exceeded those seen during placebo treatment (p < 0.01) and involved oscillations, suggesting activation of both sympathetic and parasympathetic dynamics. After ephedrine administration, arterial blood pressure increased during head-down tilt, but parasympathetic dynamics to the heart were dampened. Head-up tilt induced increased sympathetic stimulation of the heart and a sympathicotonic cardiovascular response (p < 0.01). In conclusion, midazolam induced unexpectedly great changes in dynamic cardiac control during cardiovascular stimulation. Ephedrine increased tonic sympathetic activity and stabilized the neural circulatory control of the heart by immobilizing dynamic parasympathetic activation.

Cemented revision total hip arthroplasties in patients younger than 55 years old. A multicenter evaluation of second-generation cementing technique.

The results of all cemented first-time revisions in Sweden performed in patients younger than 55 years of age, during the period 1984-1986, are reported. The revisions were performed by the average orthopaedic surgeon in 25 hospitals distributed throughout Sweden. Second-generation femoral cementing technique was used. One third of the acetabular revisions were performed with pressurized cement. The reason for revision was aseptic loosening. Seventy hips in 68 patients were reviewed at an average follow-up period of 7 years (range, 4-10 years). The average age of the patients at the time of revision surgery was 47 years. Forty-eight cups and 57 stems were revised using cement. Survival analysis, with revision for aseptic loosening as the endpoint, suggests an overall 76% survival rate after 8 years. The survival rate for the cup was 80%, and for the stem, 85%. The radiographic evaluation revealed that the cement mantle was inadequate in many revisions. Localized osteolysis was rare. Clinical data were reported for 55 (53 patients) non-revised hips. Thirty-five hips were without pain or slightly painful. Forty patients limped when walking. Forty-three patients were satisfied with the revised hip. These results using second-generation femoral cementing technique are better than those reported with first-generation technique, but the failure rate in this young patient population is too high. The search for a more durable fixation in revision total hip athroplasty for young patients with long life expectancy is ongoing. These results emphasize that there is a need for centralization to gain experience in extended clinical research and to further improve surgical and cementing techniques.

Radiographic risk signs for loosening after cemented THA: 61 loose stems and 23 loose sockets compared with 42 controls.

The 1-year radiographs in 61 stems and 23 sockets, later revised because of aseptic loosening, were carefully examined for changes such as 1) separation of the lateral side of the stem from the cement, 2) radiolucent zones at the bone-cement interface, 3) fracture of the cement, 4) endosteal cavitation and 5) migration. They were compared with 42 clinically and radiographically successful primary total hip arthroplasties with 12-16 years follow-up. We found an increased risk of loosening in hips where radiolucencies appeared within the first postoperative year, whereas an unchanged radiographic appearance after 1 year strongly indicated that the risk of later loosening was small. Patients at risk should be followed indefinitely to detect progressive loosening and concomitant bone resorption in time.

Surgically assisted, rapid maxillary expansion in adults. A retrospective long-term follow-up study.

This study presents a technique for surgically assisted, rapid maxillary expansion performed on 20 patients and the results after orthodontic treatment. The mean age of the patients was 36.3 years and on average they had been followed-up for 3 years and 6 months. The results seemed to be reliable long-term. The definitive expansion in the first molar region was 7.1 mm +/- 2.4 and in the canine region 4.8 mm +/- 2.7. The relapse measured after the observation period, was in the corresponding regions 1.2 mm +/- 1.3 and 0.2 mm +/- 2.1. The study also seemed to support the theory that the suture, anterior to the incisive canal, never ossifies until very late in life.

Angiotensin II receptor subtypes and phosphoinositide hydrolysis in rat adrenal medulla.

Angiotensin II (ANG) receptor subtypes were characterized by quantitative autoradiography after incubation with the ANG agonist [124I]Sar1-ANG in rat adrenal medulla. ANG receptors are highly localized in adrenal medulla. Specific binding was displaced by 4% and by 95% with the AT, receptor blocker losartan and the AT2 receptor competitor CGP 42112A, respectively. Analysis of competition curves indicated relative binding potencies for the AT2 population of CGP 42112A>PD 123319> PD 123177. ANG stimulated +-nositol phosphate formation in a dose-dependent manner in rat adrenal medulla. Losartan at concentrations of 10(-9) to 10(-5) M antagonized the effect of ANG, whereas PD 123177 or PD 123319 had no antagonistic action. However, at a higher concentration (10(-5) M) PD 123177 or PD 123319 potentiated the effect of ANG on InsP1-accumulation. In the presence of PD 123319 (10(-5) M) ANG dose-response curve was shifted to the left with no change in the maximal effect. This affect was blocked by the addition of losartan (10(-5) M). On the contrary, the addition of CGP 42112A (10(-6) M) inhibited ANG-induced increase in InsP1-accumulation. On the other hand, ANG and CGP 42112A reduced basal cyclic GMP formation, this effect was partially reverted by sodium orthovanadate, a phosphotyrosine phosphatase inhibitor. Our results further demonstrate the presence of two ANG receptor subtypes in adrenal medulla: ANG binding to AT, receptor stimulates inositol phospholipid metabolism, whereas ANG binding to AT2 receptors decreases both inositol phosphate production and cGMP formation.

A multicenter 10-year study of cemented revision total hip arthroplasty in patients younger than 55 years old. A follow-up report.

In 1988, the authors reported the results of 67 cemented revision total hip arthroplasties performed for aseptic loosening in patients younger than 55 years old. Both components were cemented at both the primary operation and revision. With an average follow-up period of 4 years, 14 hips (21%) required a second revision arthroplasty. Eight hips in this study group were revised using the Christiansen prosthesis, which is known to have a high failure rate and is, consequently, not in use anymore. Therefore, these eight hips have been excluded from this extended follow-up study. The authors were able to follow the remaining 59 hips for an average of 10 years (range, 8-13 years). In all, 49 hips (83%) were rerevised or radiographically loose or painful. Nevertheless, 75% of the patients, rerevisions included, were satisfied with the final result. There was an increase in bone loss at the final follow-up visit compared to the initial revision, reducing the prerequisites for a good result if further revision surgery was to be performed. After 10 years, survivorship analysis depicted a 48% survival rate when rerevision for aseptic loosening was considered a failure. The survival rate was 65% for the cup and 61% for the stem. The authors conclude that there is an increased failure rate with longer follow-up periods for cemented, revision total hip arthroplasties in young and active patients, and therefore, these patients must be followed indefinitely. The long-term results in this study provide an opportunity for valid comparisons of more sophisticated surgical techniques.

Angiotensin AT2 receptor stimulation increases survival in gerbils with abrupt unilateral carotid ligation.

Previous studies showed that angiotensin II (AII) infusion increased survival in gerbils subjected to abrupt unilateral carotid ligation. Recently, stimulation of the AII AT2 receptor, reportedly effectively extended the blood pressure (BP) range of cerebral blood flow (CBF) autoregulation. We evaluated the survival of gerbils treated with PD-123319, a ligand of AT2 receptors, to test the hypothesis that restoration of BF to ischemic cerebral tissue produced by AII is mediated through AT2 receptors. Abrupt unilateral carotid ligation was performed on 300 gerbils. In five experimental groups, animals received no drug pretreatment: (a) saline; (b)-(d) PD-123319 1.0, 3.0, and 10 mg/kg; and (e) losartan 10 mg/kg. In three additional experimental groups, animals were pretreated with enalaprilat: (f) saline; (g) PD-123319, 10 mg/kg, and (h) losartan, 10 mg/kg. Survival for 48 h was significantly improved by PD-123319 (10 mg/kg) (p < 0.05) and by losartan (10 mg/kg) (p < 0.05) as compared with animals injected with saline. Pretreatment with enalaprilat neutralized the protective effect of losartan. PD-123319 is an AT2 agonist and improved survival in this animal model of stroke. Losartan, an AT1 antagonist, also improved survival, possibly through renin release and AT2 stimulation by endogenous AII. This effect was neutralized by enalaprilat.