BOK controls apoptosis by Ca2+ transfer through ER-mitochondrial contact sites

Calcium transfer from the endoplasmic reticulum (ER) to mitochondria is a critical contributor to apoptosis. B cell lymphoma 2 (BCL-2) ovarian killer (BOK) localizes to the ER and binds the inositol 1,4,5-trisphosophate receptor (IP3R). Here, we show that BOK is necessary for baseline mitochondrial calcium levels and stimulus-induced calcium transfer from the ER to the mitochondria. Murine embryonic fibroblasts deficient for BOK have decreased proximity of the ER to the mitochondria and altered protein composition of mitochondria-associated membranes (MAMs), which form essential calcium microdomains. Rescue of the ER-mitochondrial juxtaposition with drug-inducible interorganelle linkers reveals a kinetic disruption, which when overcome in Bok^−/− cells is still insufficient to rescue thapsigargin-induced calcium transfer and apoptosis. Likewise, a BOK mutant unable to interact with IP3R restores ER-mitochondrial proximity, but not ER-mitochondrial calcium transfer, MAM protein composition, or apoptosis. This work identifies the dynamic coordination of ER-mitochondrial contact by BOK as an important control point for apoptosis.

Carpio et al. demonstrate that the proapoptotic BCL-2 family member BOK is present in mitochondrial associated membranes (MAMs). The interaction of BOK with the IP3Rs is critical for its regulation of Ca²⁺ transfer to the mitochondria, ER-mitochondrial contact sites, and apoptosis.

[Response to treatment with interferon beta in patients with multiple sclerosis. Validation of the Rio Score]

INTRODUCTION

Different criteria have been proposed for the response to treatment with interferon beta, and the Rio Score is one of the most widely used. The aim of this study was to validate the usefulness of the Rio Score in an independent cohort.

PATIENTS AND METHODS

A multi-centre, prospective, longitudinal study was conducted on patients with relapsing-remitting multiple sclerosis treated with interferon beta. The patients were classified according to the presence of attacks, active lesions (new in T2 or gadolinium enhancing lesions) in magnetic resonance imaging, a confirmed increase in disability or combinations of these variables (attacks, increase on the Expanded Disability Status Scale and active lesions) after one year's treatment. Regression analysis was used in order to identify the response-predicting variables after a three-year follow-up.

RESULTS

The sample consisted of 249 patients with relapsing-remitting multiple sclerosis. The logistic model confirmed that the presence of two (odds ratio = 6.6; CI 95% = 2.7-16.1; p < 0.0001) or three (odds ratio = 8.5; CI 95% = 1.6-46; p < 0.01) positive variables during the first year of treatment were indicative of a significant risk of activity (attacks or progression) in the next two years.

CONCLUSIONS

The usefulness of the Rio Score is confirmed, in an independent cohort, as a means of identifying patients with a higher risk of developing clinical activity or progression of disability during treatment with interferon beta.

SPECT-CT in the localization of an ectopic retropharyngeal parathyroid adenoma as a cause for persistent primary hyperparathyroidism

A common cause for surgical failure of primary hyperparathyroidism (pHPT) is the non-detection of an ectopic adenoma during the intervention. We present a case of a patient with pHPT in whom an ectopic gland was found in the right retropharyngeal space by means of a double phase (99m)Tc-methoxy-isobutyl-isonitrile ((99m)Tc-MIBI) scintigraphy and early SPECT-CT after several surgeries and imaging tests. The addition of a tomography to the planar scintigraphy increases its sensitivity and improves pathological parathyroid glands localization. The hybrid imaging is sometimes essential to obtain surgical success, as in the case of ectopic adenomas.

Defining the concept of 'tick repellency' in veterinary medicine

Although widely used, the term repellency needs to be employed with care when applied to ticks and other periodic or permanent ectoparasites. Repellency has classically been used to describe the effects of a substance that causes a flying arthropod to make oriented movements away from its source. However, for crawling arthropods such as ticks, the term commonly subsumes a range of effects that include arthropod irritation and consequent avoiding or leaving the host, failing to attach, to bite, or to feed. The objective of the present article is to highlight the need for clarity, to propose consensus descriptions and methods for the evaluation of various effects on ticks caused by chemical substances.

Decreased frontal choline and neuropsychological performance in preclinical Huntington disease

OBJECTIVES

To study metabolic brain changes in preclinical carriers of Huntington disease (PreHD) using proton magnetic resonance spectroscopy (1H-MRS) and to examine their relationship to neuropsychological performance.

METHODS

Seventeen subjects with PreHD and 17 controls, matched for age and education, were studied. Frontal cortex and basal ganglia 1H-MRS, and a detailed neuropsychological battery, including visuomotor integration and speed, and memory, frontal, and visuospatial tests were performed. Statistical analysis included Student t-test and Pearson correlations (significance p < 0.05).

RESULTS

Frontal choline-containing compounds (CHO) were decreased in PreHD [t (32) = -2.834, p = 0.008]. Subjects with PreHD performed worse than controls in the 15-Objects test [t (32) = 4.077, p = 0.000], Luria motor alternances [t (32) = -2.094, p = 0.044], and Symbol Digit tests [t (32) = -2.136, p = 0.040]. Decreased frontal CHO in PreHD correlated to slowing in visuomotor tasks (the 15-Objects test: r = -0.60, p = 0.000, and the Symbol Digit: r = 0.37, p = 0.047).

CONCLUSION

As choline-containing compounds relate to membrane turnover, membrane dysfunction antedating neuronal death is suggested to occur in the frontal cortex in preclinical carriers of Huntington disease. This dysfunction may be responsible for some of the neuropsychological deficits observed.

Evaluation of Clinical, Macroscopic, and Histopathologic Response to Treatment in Nonhypoproteinemic Dogs with Lymphocytic-Plasmacytic Enteritis

BACKGROUND

Lymphocytic-plasmacytic enteritis (LPE) is a common cause of chronic vomiting and diarrhea in dogs. However, little information is available about endoscopic or histopathologic improvement after therapy in dogs with LPE.

HYPOTHESIS

The objective was to study the clinical, endoscopic, and histopathologic evolution of LPE during and after immunosuppressive treatment with prednisone and metronidazole. Most dogs also were treated symptomatically with metoclopramide and cimetidine.

ANIMALS

Sixteen dogs with LPE and normal serum protein concentrations diagnosed at the Veterinary Medical Teaching Hospital of the Complutense University of Madrid were monitored during and after drug treatment. The control group consisted of 9 dogs that had no gastrointestinal signs for the preceding 12 months.

METHODS

In this prospective clinical treatment trial, clinical, endoscopic, and histopathologic scores were evaluated to describe disease evolution during conventional therapy. Dogs with LPE were monitored for 120 days from the start of treatment. Re-evaluation was performed on post-treatment days 30, 60, 90 (end of treatment), and 120.

RESULTS

The average disease activity index observed in our study fell progressively from its initial value, and the decrease between consecutive re-evaluations was statistically significant until day 60 (P = .04). Our results indicate that 75% of the animals revealed improvement of endoscopic gastric lesions (defined as a reduction of the endoscopic score) after treatment, and 75% exhibited improvement of endoscopic duodenal lesions. Statistical analysis of the data revealed significant differences between pre- and post-treatment gastric and duodenal macroscopic endoscopic lesions (P < .05). On the other hand, treatment did not lead to any significant changes in the severity of the gastric and duodenal histopathologic lesions of the affected dogs.

CONCLUSIONS AND CLINICAL IMPORTANCE

Treatment of nonhypoproteinemic dogs with LPE led to clinical and endoscopic improvement, but histopathologic lesions were unchanged during therapy.

Genetic characterization of Anaplasma (Ehrlichia) platys in dogs in Spain

This paper reports the first genetic characterization of Anaplasma (Ehrlichia) platys in Spain from a naturally infected dog. The dog presented clinical signs compatible with canine ehrlichiosis. After DNA extraction and PCR amplification, 16S rRNA gene and citrate synthase gene ( gltA) of this agent were amplified. The GenBank accession number for the nucleotide sequence of the 16S rRNA gene of this strain is AY530806. The A. platys strains registered in France and Japan showed the highest similarity to the 16S rRNA gene sequence obtained from the Spanish strain. In the amplification of the gltA gene, a 1443 bp fragment was obtained, and three nucleotide differences were detected in comparison with other strains sequences. These data confirm the presence of A. platys in a dog showing clinical signs compatible with ehrlichiosis in Spain.

Influence of the very polluted inputs of the Tinto-Odiel system on the adjacent littoral sediments of southwestern Spain: a statistical approach

A spatial and temporal analysis (period 1990-2003) of 15 sampling points distributed along the southwestern Spanish coast permits to delimitate the influence area of the extremely polluted discharges coming from the Tinto-Odiel system in the bottom sediments of the adjacent littoral area. As, Cu, Pb and Zn are the main heavy metals transported by the freshwater runoffs toward the shallow shelf and present very high negative (r < -0.7) and significant (p < 0.001) correlations with the distance to the estuarine mouth. The statistical analysis (index of geoaccumulation, Pearson correlation matrix, cluster analysis) of their concentrations in the littoral sediments located between the Guadiana and Guadalquivir mouths delimitates three zones: (a) Zone 1 (from the estuarine mouth to 6 km to the east), characterized by moderate to strongly polluted bottom sediments and main responsible of the mean annual variations of the former heavy metals in the area studied; (b) Zone 2 (from 21.2 km to the west to 29 km to the east), characterized by moderate pollution levels; and (c) Zone 3, located near the Guadiana and Guadalquivir mouths, with very low As-Cu-Pb contents and unpolluted to moderately levels of Zn due to urban sewages or the presence of local low mobility areas for this element.

[Esophageal atresia type I. Is impossible possible?]

INTRODUCTION

Treatment of esophageal atresia with "long gap" remains difficult and controversial. According to the idea that esophageal anastomosis is imposible in most cases, several esophageal substitution methods have been proposed, as esophagocoloplasty, gastric transposition or reversed gastric tube. Nevertheless reconstruction of native esophagus is accepted as the best option if posible. "Long gap" definition is imprecise, expressed by variability in percent of these cases in total esophageal atresias reported in different series in literature. We report our experience in seven cases type I esophageal atresia with long gap and the different therapeutic options used, with attention to delayed or early esophageal anastomosis feasibility and outcome.

MATERIAL AND METHODS

We have treated 121 patients with esophageal atresia from whom we analized 7 cases with pure esophageal atresia with "long gap" (5.8%). Six patients underwent gastrostomy and two gastrostomy and esophagostomy. Five patient underwent primary repair with esophageal anastomosis, delayed between 14 days and 4 months in 4 cases. One patient underwent esophageal anastomosis in the first day without gastrostomy. Retroesternal esophagocoloplasty was performed in 2 patients about their first year of life. Esophagogram was done in first month after surgery and pH monitoring of gastroesophageal reflux. Follow-up ranged from 6 months to 28 years.

RESULTS

Esophageal anastomosis was feasible in all 5 patients in whom it was tried. Stricture occurred in two patients, one patient underwent anastomotic resection and new esophageal anastomosis. Esophageal reflux was present in two patients, one of them required funduplication. One patient was dead by complications of cardiac malformation. Remaining patients have normal swallowing and are in normal growth curves. Patients with esophagocoloplasty had not relevant early or late complications.

CONCLUSIONS

In most pure esophageal atresia, delayed or even early esophageal anastomosis is feasible, making use of surgical and anesthesic sources that favour it. Esophageal substitution techniques can be reserved if this approach fails.

Application of a systemic approach to the study of pollution of the Tinto and Odiel rivers (Spain)

The province of Huelva in the SW of Spain presents high environmental contrasts: together with the great abundance of natural spaces, it shows the impacts of historical natural resources exploitation processes. In the Ria of Huelva, the effluents of the chemical industries must be added to the contaminating inputs of the Tinto and Odiel rivers, coming from the acid drainage of the mines located in the Iberian Pyrite Belt. This forced the Environmental Agency (AMA) to elaborate in 1987 an Effluent Remediation Plan in order to negate unacceptable environmental impacts. The application of a "grey box" systemic analysis to the AMD pollution, undergone by the Tinto and Odiel rivers has allowed to set a conclusive explanation of the sampling results observed for a period of 11 years, thus making available an overall view of the polluting process and, above all, an explanation of its partial aspects.

Characterisation of heavy metal discharge into the Ria of Huelva

The Ria of Huelva estuary, in SW Spain, is known to be one of the most heavy metal contaminated estuaries in the world. River contribution to the estuary of dissolved Cu, Zn, Mn, Cr, Ni, Cd, and As were analysed for the period 1988-2001. The obtained mean values show that this contribution, both because of the magnitude of total metals (895.1 kg/h), composition, toxicity (8.7 kg/h of As+Cd+Pb) and persistence, is an incomparable case in heavy metal contamination of estuaries. The amount and typology of heavy metal discharge to the Ria of Huelva are related to freshwater flow (and, consequently, to rainfall); as a result, two different types of heavy metal discharge can be distinguished in the estuary: during low water (50% of the days), with only 19.3 kg/h of heavy metals, and during high water or flood (17% of the days), where daily maximum discharge of 72,475 kg of heavy metals were recorded, from which 1481 kg were of As, 470 kg of Pb, and 170 kg of Cd. In the most frequent situation (77% of the days), the Odiel River discharges from 90% to 100% of the freshwater received by the estuary. Despite this, the high concentration of heavy metals in the Tinto River water causes this river to discharge into the Ria of Huelva 12.5% of fluvial total dissolved metal load received by the estuary.

Distribution and relationships between clinical and biopathological parameters in canine leishmaniasis

Although the lesions, clinical signs and biochemical alterations observed in the course of canine leishmaniasis have been amply described a thorough definition and characterisation of the affected populations is important in order to detect relationships between parameters which may be involved in the development of this disease and to correctly assess further studies. This study included 61 dogs diagnosed with naturally acquired canine leishmaniasis by means of indirect immunofluorescence assay (IFA). At diagnosis, dogs were classified according to the following qualitative and quantitative variables: gender, breed, age, clinical picture, antibody titre, serum protein electrophoretogram, haemogram (CBC), urea, creatinine and ALT. Our population included dogs of 24 breeds, both sexes and different ages indicating no sex, age or breed predilection. In relation to the clinical picture, eight dogs were asymptomatic, 16 displayed mainly cutaneous signs, 18 presented primarily visceral signs and 19 displayed both cutaneous and visceral signs. Our results indicate that the clinical picture is significantly related to electrophoretogram and to RBC, PCV and haemoglobin. Dogs with mainly cutaneous signs showed the highest eosinophil mean values and those with mainly visceral signs showed the highest alpha-globulin mean values. This study confirms that the antibody titre is highly correlated with electrophoretogram and with RBC, PCV and haemoglobin. Lymphocytes were not associated or correlated with any other variable considered. PMNC, monocytes and eosinophils, as well as WBC, showed a significant correlation with beta-globulins, which is difficult to interpret.

Drosophila melanogaster and D. simulans rescue strains produce fit offspring, despite divergent centromere-specific histone alleles

The interaction between rapidly evolving centromere sequences and conserved kinetochore machinery appears to be mediated by centromere-binding proteins. A recent theory proposes that the independent evolution of centromere-binding proteins in isolated populations may be a universal cause of speciation among eukaryotes. In Drosophila the centromere-specific histone, Cid (centromere identifier), shows extensive sequence divergence between D. melanogaster and the D. simulans clade, indicating that centromere machinery incompatibilities may indeed be involved in reproductive isolation and speciation. However, it is presently unclear whether the adaptive evolution of Cid was a cause of the divergence between these species, or merely a product of postspeciation adaptation in the separate lineages. Furthermore, the extent to which divergent centromere identifier proteins provide a barrier to reproduction remains unknown. Interestingly, a small number of rescue lines from both D. melanogaster and D. simulans can restore hybrid fitness. Through comparisons of cid sequence between nonrescue and rescue strains, we show that cid is not involved in restoring hybrid viability or female fertility. Further, we demonstrate that divergent cid alleles are not sufficient to cause inviability or female sterility in hybrid crosses. Our data do not dispute the rapid divergence of cid or the coevolution of centromeric components in Drosophila; however, they do suggest that cid underwent adaptive evolution after D. melanogaster and D. simulans diverged and, consequently, is not a speciation gene.

Odiel River, acid mine drainage and current characterisation by means of univariate analysis

Water pollution caused by sulfide oxidation responds to two geochemical processes: a natural one of temporal patterns, and the 'acid mine drainage', an accelerated process derived from the extractive activity. The Odiel River is located in Southwestern Spain; it flows to the south and into the Atlantic Ocean after joining the Tinto River near its mouth, forming a common estuary. There are three kinds of metallic mining in the Odiel River Basin: manganese, gold and silver, and pyrite mining, the latter being the most important in this basin, which is the object of this study. The main objective of the present study is centred in the characterisation of the sources responsible for the 'acid mine drainage' processes in the Odiel River Basin, through the sampling and subsequent chemical and statistical analyses of water samples collected in three types of sources: mine dumps, active mines and abandoned mines. The main conclusion is that mean pH values in the target area are remarkably lower than those in other active and abandoned mines outside of the study zone. On the contrary, mean values for heavy metal sulfates are much higher. Regarding mine dumps, mean values for pH, sulfates and heavy metals are within a similar range to those data known for areas outside the study zone.

A polychaete hunchback ortholog

We report the first characterization of a segmentation gene homologue in the basal polychaete Capitella capitata using a pan-annelid cross-species antibody to the hunchback-like gene product. In flies, the gap segmentation gene hunchback (hb) encodes a C(2)H(2) zinc-finger transcription factor that plays a pivotal role in patterning the anterior region of the fly body plan. The hb orthologue in Capitella (Cc-hb) is expressed maternally and in all micromere and macromere cells throughout cleavage. At gastrulation, nuclear Cc-hb protein is expressed in the micromere-derived surface epithelium that undergoes epiboly and in the large vegetal blastomeres that gradually become internalized. During organogenesis, Cc-hb is expressed in the developing gut epithelium, the prostomial and pygidial epithelium, and in a subset of differentiated neurons in the adult central nervous system. Cc-hb is not expressed in the segmental precursor cells in the trunk. The Cc-hb expression domains in Capitella are similar to those reported for the leech hb orthologue (LZF2), and many of the observed differences between the annelid classes correlate with changes in life history. The lack of detectable annelid hb protein in the trunk at the time of AP pattern formation in leech and in polychaete suggests that the anterior organizing function of hb in flies originated in the arthropod or insect lineage.

Standardization of the diagnostic criteria for canine ehrlichiosis. Towards a universal case definition

Canine ehrlichiosis is a highly variable syndrome presenting a significant differential diagnostic difficulty. It imitates many metabolic and infectious diseases and lacks standardized diagnostic criteria, common reagents, and database resources. A clinical diagnosis of canine ehrlichiosis may be based on the manifestation of fever, thrombocytopenia, anorexia, nasolacrimal discharge, epistaxis, and exclusion of autoimmune and common canine vector borne diseases. These parameters are not invariably observed especially in the atypical form of the disease often caused by species other than Ehrlichia canis. A definitive diagnosis is based on the presence of specific antibodies to ehrlichial agent(s), the demonstration of the etiologic agent(s) itself, or specific amplicons by a strigently quality controlled PCR protocol. The relationship of the various clinical and laboratory parameters, the status of the currently available tests, and their real or presumed predictive value are discussed in the context of stimulating an effort to formulate an international standard for the diagnosis of this and related diseases of man and animals.

Creating experimental analogs with available clinical information: credible alternatives to "gold-standard" experiments?

Comparison of the implementation and findings of a "gold standard" evaluation of social work intervention and its experimental analog based on available clinical information illustrates the strengths and weaknesses of each. From a practice-research integration perspective, however, "clinical data-mining" may be a credible alternative to randomized controlled experiments.

Prospective comparative study of 3 treatment protocols using doxycycline or imidocarb dipropionate in dogs with naturally occurring ehrlichiosis

This paper reports the clinicopathologic responses of 93 dogs with spontaneously occurring ehrlichiosis to 3 different treatment protocols. Thirty-two dogs were treated with doxycycline (10 mg/kg/day for 28 days), 31 were treated with imidocarb dipropionate (5 mg/kg given 15 days apart in 2 separate injections), and 30 were treated with both drugs simultaneously, at the doses as specified. The dogs underwent clinicopathologic evaluation before and after treatment, and were examined periodically during the 24-month period after the treatment. No differences were found in the clinical responses among the dogs in the 3 treatment groups. As for the clinicopathologic response, in spite of the fact that at the end of the study the results obtained with the 3 protocols were similar, the platelet count and serum protein electrophoresis results returned to normal more slowly in dogs that received imidocarb dipropionate as compared to those given the other 2 treatments.

Pharmacological and dietary treatment of canine malabsorption syndrome: a retrospective study of 17 clinical cases

The present study deals with the symptomatology, diagnosis (by means of gastroduodenoscopy and biopsy) and response to a combined dietary/immunosuppressive pharmacological treatment of 17 dogs with malabsorption syndrome. Clinical signs, body weight and serum protein levels evolved favourably in all individuals included in this study during the 150 days following initiation of treatment.

Impediments to the discharge planning effort for psychiatric inpatients

OBJECTIVE

This study investigates a methodology to systematically track the effort to overcome impediments to securing needed post-hospital care and support.

METHODS

494 consecutive admissions to the Mount Sinai Medical Center were evaluated for the quality of available support resources in the domains of housing, daily activity, and psychiatric treatment using the Mount Sinai Discharge Planning Inventory. On day seven, the same rater recorded the optimal discharge plan for each resource category and those impediment codes that were likely to interfere with attaining the desired resource. On discharge, the rater recorded the actual resources obtained for the patient, and if the plan did not meet the patient's needs, an impediment code was used to explain why the sub-optimal "discharge fit" was not secured.

RESULTS

Having an impediment in any of the three resource categories (housing, daily activities, psychiatric treatment services) at day 7 was predictive of a sub-optimal discharge plan. Of all three resource categories studied, a decline in overall impediments from day 7 to discharge was significant only for psychiatric treatment services. An internal/clinical impediment in any of the three resource categories on day 7 was associated with a patient history of alcohol and drug abuse. A significant association was found between having external/environmental impediments identified at discharge for housing and psychiatric treatment services with return to the hospital within 90 days of discharge.

CONCLUSION

Study of the impediments to the discharge planning effort provides an opportunity to elucidate the factors that comprise the pathway of recovery from psychiatric illness, but which are normally ill-defined, poorly understood, or not readily measured.

Hematological and plasma biochemical reference intervals in young white storks

Hematological and plasma chemistry parameters were measured in 129 juvenile white storks (Ciconia ciconia), either wild or captive bred, April to June 1994. Wild storks were members of a colony in the Lozoya River Valley, Madrid, Spain. Red blood cells count, packed cell volume and hemoglobin increased significantly with age. White blood cells count, lymphocytes count and platelets decreased with age. Total solids, total proteins, fibrinogen, albumin, alpha, beta, gamma-globulins and urea increased with age. Differences between captive and wild birds were not notable.

Influences on fit between psychiatric patients' psychosocial needs and their hospital discharge plan

OBJECTIVE

The study examined factors that help determine a good or poor fit between the psychosocial support needs of hospitalized patients and the hospital's discharge plan.

METHODS

The Mount Sinai Discharge Planning Inventory was completed weekly for 494 consecutive admissions to the hospital's adult inpatient psychiatric units. The resources that patients brought with them into the hospitalization in the areas of housing, entitlements, daily activities, and psychiatric treatment were recorded as well as the resources that would constitute an optimal discharge plan. Good or poor fit was operationally defined by the match between the optimal, first-choice plan and the implemented discharge plan.

RESULTS

One-third of admissions were found to have an optimal fit on admission in all resource categories studied. For patients who entered the hospital with suboptimal resources, discharge planing was significantly more likely to establish clinically relevant psychiatric treatment options and to strengthen daily living activities than to change housing resources. Certain diagnoses and a history of drug abuse, criminality, violence, and treatment noncompliance were associated with poorer fits with first-choice disposition options.

CONCLUSIONS

The Mount Sinai Discharge Planning Inventory provides a method to systematically evaluate discharge planning by tracking progress toward securing relevant posthospital care and support.

Immunohistological study of IgA, IgG and IgM in endoscopic biopsies of dogs with plasmacytic-lymphocytic colitis

The results of a histological and immunohistochemical study of endoscopic colon biopsies of dogs with plasmacytic-lymphocytic colitis are reported. The histological study revealed that a characteristic infiltrate rich in lymphocytes and plasma cells was seen within the lamina propria in all the biopsies. The immunohistochemical investigation suggests that IgG is the major antibody in the immune response of dogs with plasmacytic-lymphocytic colitis.

Deceleration vs. acceleration: a haemodynamic parameter in the assessment of vascular reactivity. A preliminary study

The parameter deceleration vs. acceleration (dc/ac) as derived from the instantaneous peak velocity is obtained by dividing the descending and ascending slopes of plotted velocity curves. Blood velocities were recorded with a specially designed continuous-wave ultrasonic Doppler unit which provides: the instantaneous peak velocity, the instantaneous mean velocity, the acceleration, and an indication of volume flow. A physical meaning to the dc/ac parameter is given through an analysis, based on an electrical model, of a small portion of an artery. This gives a simple relationship which only takes account of the assumed vascular resistances. Measurements were performed in 67 male subjects; 39 were normotensive control subjects and 28 had established moderate hypertension. In both groups there was an increase of dc/ac in passing from the supine to the erect position, the increase being more accentuated by hypertension. The variation of dc/ac with age was significantly different in both groups. The results suggest that this parameter is a sensitive indicator of variations in vascular reactivity and as an indicator of structural changes in the arterial wall.

A simple module for on-line computation of stroke volume and cardiac output

An easily constructed, low-priced, simple, and reliable module to obtain stroke volume and cardiac output by analog integration of aortic blood flow velocity signals is described. Rapid data analysis of physiologic and pharmacologic cardiovascular responses in dogs is greatly facilitated by on line computation of these parameters.