Calamistrins A and B, two new cytotoxic monotetrahydrofuran annonaceous acetogenins from Uvaria calamistrata

Two new bioactive monotetrahydrofuran acetogenins, calamistrins A (1) and B (2), and two known compounds, uvarigrin (3) and uvarigranin (4), have been isolated from the roots of Uvaria calamistrata. The structures of the new compounds were elucidated by spectroscopic and chemical methods. The absolute stereochemistry of the stereogenic centers was established by Mosher ester methodology.

New polyoxygenated cyclohexenes from Uvaria calamistrata

Five new polyoxygenated cyclohexenes, named uvacalol A (1), B (2), C (3), D (4) and E (5) were isolated from the roots of Uvaria calamistrata. On the basis of spectral analysis and chemical derivatization, including the preparation of Mosher esters, the structures of compound 1-5 were established as (2R,3S,4R,5S)-2-acetoxyl-5-ethoxyl-1-benzoyloxymethylcyclohex-1(6)-ene3,4-diol-3-benzoate, (2R,3S,4R,5S)-2-acetoxyl-5-ethoxyl-1-benzoyloxymethylcyclohex-1(6)-ene-3,4-diol-4-benzoate, (2R,3S,4R,5S)-5-ethoxyl-1-benzoyloxymethylcyclohex-1(6)-ene-2,3,4-triol-3-benzoate, (2R,3S,4R,5S)-3-methoxyl-1-benzoyloxymethylcyclohex-1(6)-ene-2,3,5-triol and (2R,3S,4R,5S)-2-acetoxyl-1-benzoyloxymethylcyclohex-1(6)-ene-3,4,5-triol-5-benzoate, respectively.

Styryllactones from the rhizomes of Goniothalamus griffithii

Three new styryl-lactones 8-acetylgoniofufurone(1), 7-acetylgonio-pypyrone(3), and 5-acetylgoniopypyrone(4), along with ten known compounds, goniofufurone(2), goniopypyrone(5), goniothalamin, goniothalenol, (+)-isoaltholactone, goniodiol, 7-acetylgoniodiol, goniotriol, 8-acetylgoniotriol, 9-deoxygoniopypyrone were isolated from the rhizomes of Goniothalamus griffithii Hook f. et. Thoms. Their structures were elucidated by IR, MS, NMR spectra and chemical evidence. All compounds showed cytotoxic activities against human cancer cell lines.

Construction of a DNA library from chromosome 4 of rice (Oryza sativa) by microdissection

A simple method to create a chromosome-specific DNA library of rice, including microdissection, amplification, characterization and cloning, is described. Rice chromosome 4 from a metaphase cell has been isolated and amplified by the Linker Adapter PCR (LA-PCR). The PCR products were labeled as probes with DIG-11-dUTP using the random priming method. Southern blot analysis with rice genomic DNA and specific RFLP markers demonstrated that the PCR products were derived from rice chromosome 4. A large library comprising over 100,000 recombinant plasmid microclones from rice chromosome 4 was constructed. Colony hybridization showed that 58% of the clones contained single or low-copy sequences and 42% contained repetitive sequences. The size of inserts generated by PCR ranged from 140bp to 500bp. This method will facilitate cloning of the specific chromosome DNA markers and important genes of rice.

Estimation of target hazard quotients and potential health risks for metals by consumption of seafood in Taiwan

The purpose of this paper is to describe the impact of metal pollution on the main seafood and assess the potential health risk from consuming the contaminated seafood in Taiwan. The results of geometric mean (GM) metal concentrations in various seafood showed that the copper, zinc, and arsenic concentrations in oysters were significantly (p < 0.001) higher than those in the other seafood by about 1,057, 74.3, and 56.2 times, respectively. The green color found in the oysters was due to high GM copper and zinc concentrations of 909 (ranging from 113-2,805) and 1,293 (ranging from 303-3,593) microg/g dry wt, respectively. In addition, using a maximum consumption rate of 139 g/day of oysters for individuals, calculations yield target hazard quotients (daily intake/reference dose) of below 1 for cadmium and mercury and high values of 1.61, 9. 33, and 1.77 for inorganic arsenic, copper, and zinc in adults, respectively. The various lifetime cancer risks for inorganic arsenic (maximum exposed individuals risk ranging from 9.93 x 10(-6) to 3.11 x 10(-4)) might be caused by consuming different seafood in Taiwan. The highest risk estimate for inorganic arsenic was 5.10 x 10(-4) for consumption of oysters by Machu Islands residents. The long-term exposure of metals through consumption of oysters, especially for some high-risk groups, could be dangerous. Taking inorganic arsenic for example, a 10(-6) upper limit on lifetime risk as the health protection standard would require maximum oyster residue levels of approximately 0.0076-0.056 microg/g wet wt, for consumption rates of 139-18.6 g/d. In the light of known risks to public health, the government should issue an immediate warning to the public to refrain from eating all seafood harvested from the Taiwan coastal areas, especially the Hsiangshan area and the Machu Islands.

Linear acetogenins from Goniothalamus donnaiensis

Four linear acetogenins, donhepocin (1), 34-epi-donhepocin (1'), donhexocin and donbutocin, have been isolated from the roots of Goniothalamus donnaiensis. 1 and 1', isolated as an epimeric pair, contain a rare gamma-hydroxymethyl-gamma-lactone. Their structures have been established on the basis of spectral and chemical evidence.

Two epimeric pairs of C-4-acetyl annonaceous acetogenins from Goniothalamus donnaiensis

Further studies on the roots of Goniothalamus donnaiensis Finet et Gagnap (Annonaceae) led to the isolation of two pairs of Annonaceous acetogenins, donnaienin C ( 1) and 34- EPI-donnaienin C ( 1'), donnaienin D ( 2) and 34- EPI-donnaienin D ( 2'), containing a rare gamma-hydroxymethyl-gamma-lactone moiety and a C-4-acetoxy group. Their structures were elucidated by spectral data and chemical derivatization. Preliminary pharmacological tests showed that the mixture of donnaienin C( 1) and 34- EPI-donnaienin C ( 1') inhibited human hepatoma (Bel) cell lines in vitro (IC (50), 7.1 microg/ml).

Donnaienin, a New Acetogenin Bearing a Hydroxylated Tetrahydrofuran Ring

A novel Annonaceous acetogenin, donnaienin (1), was isolated from the roots of Goniothalamus donnaiensis. Its structure and stereochemistry were elucidated on the basis of spectral data and chemical evidence. This compound represents an unusual type of Annonaceous acetogenin, bearing a hydroxylated tetrahydrofuran ring.

How are psychotic symptoms perceived? A comparison between patients, relatives and the general public

OBJECTIVE

The aim of this study is to compare patients with schizophrenia with their relatives and the general public in their attitudes towards schizophrenic psychotic symptoms.

METHOD

We used a case vignette depicting a person with typical schizophrenic psychotic symptoms and compared the attitudes of 44 inpatients and 47 outpatients with schizophrenia, 48 of their relatives and 43 members of the general public. We also compared the attitudes of patients with schizophrenia to their own symptoms and the symptoms described in the vignette.

RESULTS

Subjects from the general public tended not to recognise psychotic symptoms as features of mental illness and tended not to consider drug treatment and hospitalisation as required. Sex, education level as well as previous contact with the mentally ill were found to be significant determinants of attitude. The levels of symptom awareness in patients with schizophrenia and their relatives are higher but still relatively low. In addition, we found that patients with schizophrenia who correctly appraised psychotic symptoms in another person were also aware of their own mental symptoms and need of treatment.

CONCLUSIONS

The level of recognition of psychotic symptoms and awareness of a need for treatment are low in the general public, as well as in patients with schizophrenia and their relatives. These findings are discussed in relation to the assessment of insight in patients and a need for psychoeducational programs for each group.

Neuropsychological correlates of sustained attention in schizophrenia

We employed a simple and relatively undemanding task of monotone counting for the assessment of sustained attention in schizophrenic patients. The monotone counting task has been validated neuropsychologically and is particularly sensitive to right prefrontal lesions. We compared the performance of schizophrenic patients with age- and education-matched controls. We then explored the extent to which a range of commonly employed neuropsychological tasks in schizophrenia research are related to attentional impairment as measured in this way. Monotone counting performance was found to be correlated with digit span (WAIS-R-HK), information (WAIS-R-HK), comprehension (WAIS-R-HK), logical memory (immediate recall) (Weschler Memory Scale, WMS), and visual reproduction (WMS). Multiple regression analysis also identified visual reproduction, digit span and comprehension as significant predictors of attention performance. In contrast, logical memory (delay recall) (WMS), similarity (WAIS-R-HK), semantic fluency, and Wisconsin Card Sorting Test (perseverative errors) were not correlated with attention. In addition, no significant correlation between sustained attention and symptoms was found. These findings are discussed in the context of a weakly modular cognitive system where attentional impairment may contribute selectively to a range of other cognitive deficits.

Blink rate, neurocognitive impairments, and symptoms in schizophrenia

This study addresses the relationship between blink rate (as a measure of central dopaminergic activity), symptoms, neuropsychological performance, as well as neurological signs in schizophrenia. Blink rate between schizophrenic patients and a matched control group was compared in both "relaxed" and "attentive" conditions. Blink rate was increased in schizophrenic patients in the "relaxed" condition but not in the "attentive" condition. The relationship between blink rate and clinical variables was examined in a larger sample of 204 patients. In both "relaxed" and "attentive" conditions, blink rate was related to "hallucinations," "anxiety," negative symptoms, and neuroleptic dosage. Attention was a significant predictor only in the "relaxed" condition. No other significant correlation was found between blink rate, neuropsychological impairments, and neurological signs. These findings suggest that blink rate is not related to neurocognitive impairments in schizophrenia.

Neurological signs, age, and illness duration in schizophrenia

Although increased prevalence of neurological signs in schizophrenia may reflect the presence of subtle brain dysfunctions, it is not clear whether there is progressive deterioration in such neurological function as the illness advances. This study compared neurological signs in patients with different durations of illness, controlling for age and education level. No deterioration in neurological signs as a function of illness duration was observed. Although there was an increase in neurological signs with age, there was a parallel increase in a control group. In addition, no change in the profile of subgroups of neurological signs was detected. These data provide further evidence for the stability of neurological dysfunction in schizophrenia. The findings are discussed in the context of the developmental origin of neurological dysfunction in schizophrenia.

Monitoring lead pollution near a storage battery recycling plant in Taiwan, Republic of China

This study presents the distribution of blood lead levels and lead in various environmental samples (water, sediments, soils, and air) near the Shing-Yie storage battery recycling plant in Taiwan before (July 1990 to June 1991) and after (July 1992 to June 1993) amelioration. Before amelioration, the average blood lead levels in the neighborhood of the plant were in the range of 10.55 +/- 5.7 to 12.28 +/- 7.9 micrograms/dl. After amelioration, relatively lower average concentrations of blood lead (range 8.35 +/- 3.0 to 9.13 +/- 2.5 micrograms/dl) were generally found; however, these averages were still higher than that (7.79 +/- 3.5 micrograms/dl) from other lead-unpolluted areas of Taiwan. An exceedingly high geometric mean (GM) lead concentration (128 micrograms/L) was found in the downstream river water of the Tawulum River passing by the plant. The concentrations of lead (GM = 372 and 418 micrograms/g) in the downstream river sediments were higher than those (GM = 123 and 158 micrograms/g) in the upstream river sediments before and after amelioration, respectively. Furthermore, lead species in river sediments were analyzed by a sequential leaching technique. The sum of phases I, II, and III accounted for 83.7% of total lead at station R2 (nearest to the plant). Maximum lead concentration (GM = 2402 micrograms/g) in dust at the soil surface from station S1 (nearest to the plant) was much higher than those from the other stations by about 18 times before amelioration. However, the maximum value dropped to 1,155 micrograms/g after amelioration. On the whole, the geometric mean concentration of lead in dust at the soil surface nearest to the plant was > 1,000 micrograms/g and decreased to < 100 micrograms/g in the 15-30 cm depth soil about 2 km away from the plant. Before amelioration, the geometric mean lead concentration of 4.57 micrograms/m3 (range 0.102-37.6 micrograms/m3) in the air near the plant was higher than that at the background locations, the geometric mean value of which was 0.08 micrograms/m3.

Prefrontal neuropsychological impairment and illness duration in schizophrenia: a study of 204 patients in Hong Kong

Previous studies investigating the progression of neuropsychological impairment in schizophrenia have yielded conflicting results. We compared prefrontal neuropsychological function and other cognitive performance in a larger sample of schizophrenic patients with different duration of illness. The inclusion of a normal control group also allowed the effect of age to be taken into account. Performance in the Wisconsin Card Sorting Test (WCST) and semantic fluency were both impaired at an early stage in the illness and did not significantly deteriorate as the illness duration increased. Against this background there was preliminary evidence for deterioration in verbal memory function. The data support a lack of progression in prefrontal dysfunction and in most other cognitive domains.

Negative symptoms, neurological signs and neuropsychological impairments in 204 Hong Kong Chinese patients with schizophrenia

BACKGROUND

Studies of the relationship between negative symptoms, neuropsychological impairments and neurological signs in schizophrenia have yielded inconsistent results. In addition, little attention has been directed to address the extent of cultural modulation of negative symptoms.

METHOD

We carried out cross-cultural validation of the High Royds Evaluation of Negativity Scale (HEN) in 50 Hong Kong Chinese patients with schizophrenia. We then investigated the relationship between negative symptoms, neurological signs and neuropsychological impairment in 204 patients.

RESULTS

Good interrater reliability, internal reliability, convergent and discriminant validity were found with the HEN. The HEN contained four factors corresponding to 'behaviour', 'functioning', 'thought' and 'appearance'. Negative symptoms were correlated with semantic fluency but not with Wisconsin Card Sorting Test performance or sustained attention. Negative symptoms were also correlated with tardive dyskinesia and catatonia but not with soft neurological signs.

CONCLUSIONS

Cross-cultural robustness of the negative symptoms construct is supported. Association of negative symptoms with a specific profile of neurocognitive impairment suggests diversity within deficit domains in schizophrenia.

Interaction of endogenous nitric oxide and CGRP in sensory neuron-induced gastric vasodilation

Stimulation of capsaicin-sensitive sensory nerves induces gastric mucosal hyperemia, which is mediated in part by both calcitonin gene-related peptide (CGRP) and nitric oxide (NO). In the present study, we used in vivo microscopy in anesthetized rats to determine 1) whether these agents were released locally at the submucosal level and, if so, 2) whether CGRP dilates arterioles via release of endothelium-derived NO. Intragastric capsaicin (160 microM) dilated submucosal arterioles from 25 +/- 3 to 67 +/- 8 microns. The intragastric capsaicin-induced vasodilation was markedly reversed not only by intravenous administration of the NO synthesis inhibitor NG-nitro-L-arginine methyl ester (L-NAME) but also by submucosal suffusion of either L-NAME or the CGRP receptor antagonist human CGRP-(8-37). The latter findings indicate that both NO and CGRP are released locally at the submucosal level. Submucosal application of CGRP induced dose-dependent dilation of gastric submucosal arterioles, which was significantly attenuated by L-NAME. However, at the same degree of vasodilation (42 microns), the dilation induced with submucosal CGRP was much less attenuated by NO synthesis inhibition (-28%) compared with that induced with intragastric capsaicin (-79%). This indicates that endothelium-derived NO released by CGRP was not the only source of submucosal NO in the latter response. There must be another as yet undetermined source of submucosal NO, e.g., possibly nitroxidergic nerves.

Gastric arteriolar and venular responses to nitrogenous and nonnitrogenous vasodilating agents in the rat

We made in vivo microvascular observations to simultaneously compare the actions of various direct vasodilators on the resistance and capacitance vessels without confounding systemic hemodynamic effects. The responses of gastric submucosal arteriolar and venular diameters to the topical application of 10(-7) 10(-5), and 10(-3) M of the vasodilators nitroglycerin (NTG), sodium nitroprusside (SNP), hydralazine (HYD), and adenosine (ADN), and acetylcholine (ACh) were studied in 6 rats for each agent using in vivo microscopy. The basal diameters of arterioles, 37 +/- 2 microns (mean +/- SE), were maximally dilated to 86 +/- 2 microns by 10(-3) M ADN, NTG, SNP or ACh, while with 10(-3) M HYD dilation was just 55%. The basal diameters of venules, 36 +/- 2 microns, were maximally dilated only to 51 +/- 1 micron by 10(-3) M ADN, NTG or SNP, while those by 10(-3) M HYD and ACh were 60 and 71%, respectively. We observed that: (1) NTG and SNP were the strongest arteriolar and venular dilators, but at low dose (10(-7) M), NTG was more effective than SNP. (2) Gastric submucosal venules had considerably less dilating capacity than arterioles. (3) ADN was as effective as NTG and SNP for both arteriolar and venular dilation at 10(-3) M. It was less potent at lower concentrations. (4) ACh was as potent as ADN, NTG and SNP in dilating arterioles, but it was notably less potent in dilating venules. (5) HYD was the weakest arteriolar and venular dilator among all agents studied, and its action on venules was slightly greater than that on arterioles.

Role of L-arginine-derived nitric oxide in cholinergic dilation of gastric arterioles

The role of L-arginine-derived nitric oxide (NO) in cholinergic vasodilation of resistance vessels was studied in the intact stomach of the rat, utilizing an in vivo microscopy technique. Two L-arginine analogues, NG-monomethyl-L-arginine (L-NMMA) and nitro-L-arginine methyl ester (L-NAME), were used to block NO synthesis. Cholinergic dilation of gastric submucosal arterioles was induced by topical application of various concentrations of acetylcholine (ACh) (10(-7)-10(-4) M). Intravenous but not topical administration of L-NMMA and L-NAME caused an increase in arterial pressure. Intravenous or topical L-NAME reduces resting arteriolar diameter. These findings support the contention that NO formation modulates basal vascular tone and suggest that NO release may play a significant role in the regulation of the gastric circulation. L-Arginine analogues attenuated the arteriolar dilating effect of ACh but not adenosine or nitroglycerin. Substantial arteriolar responses to ACh remained after systemic or topical treatment with either L-NMMA or L-NAME. These results indicate that the L-arginine-NO pathway accounts only in part for ACh-induced vasodilation in gastric resistance vessels in vivo.

Survey of glycol ether use in Taiwan, 1991

Glycol ethers (including glycol ether esters) are a group of solvents with medium-high boiling points and low evaporation rates, possessing solvent characteristics of alcohol/ether functions (or ether/ester functions). They have been widely used in coatings and other industrial products for more than half a century. Recently, E-series glycol ethers have been found to show reproductive and teratogenic toxicity, and throughout much of the world they are being replaced by the so-called P-series glycol ethers. In responding to the impact of the worldwide transition from E- to P-series glycol ethers, the current status of glycol ether use in Taiwan was studied. This study focuses on the type and quantity of these solvents being used, worker and public knowledge about their hazards, and possible changes in government regulations being considered. In this study, we found that large quantities of E-series glycol ethers were imported and used in Taiwan. The best estimates are: 2-ME, 2,500 tons; 2-EE, 1,200 tons; 2-EEA, 5,000-8,000 tons; 2-BE, 8,000 tons annually in 1991. For P-series glycol ethers, only about 2,500 tons are being used. Lack of knowledge about the potential toxic effects of the E-series glycol ethers is very common among users, regulatory agencies, academic institutes, and the general public. It is hoped that the results of this study, along with educational efforts, government regulations, and provision of technical services, will help prevent Taiwan from becoming a dumping site for these toxic chemicals.

[Intraocular pressure and optic nerve damages in monocular early glaucoma: a comparative study of primary open angle glaucoma and low tension glaucoma]

The correlation of intraocular pressure (IOP) to optic nerve damages was studied in 17 patients of primary open angle glaucoma (POAG) and 24 patients of low tension glaucoma (LTG) both with monocular early glaucomatous damages. In the POAG group, the mean IOP was higher in the glaucomatous eye than in the other, while in the LTG group there was no significant IOP difference between the two eyes. Comparing the optic nerve damages in both groups, patients of POAG presented a concentrically enlarged cup with even disc rim and diffuse retinal nerve fiber layer defect (RNFLD), while patients of LTG exhibited a paracentrical cup with uneven disc rim and localized RNFLD. The results suggested that there could be different mechanisms of optic nerve damages in the two groups.

Antinuclear antibody detection using streptavidin-biotin-peroxidase complex on HEp-2 cell substrate

The streptavidin-biotin-peroxidase complex (SABC) technique was compared to conventional indirect immunofluorescence (IIF) for the detection of anti-nuclear antibody (ANA) on HEp-2 cell substrate. SABC showed higher specificity and predictive value and gave more reproducible titres and clearer staining patterns than IIF in sera from a series of rheumatic disease patients. Sera from 80 patients with various types of rheumatic diseases and 20 without rheumatic disease were further tested using the SABC method. All systemic lupus erythematosus (SLE) sera were positive. The overall sensitivity was 95%, specificity 90% and predictive value 97% for rheumatic disease. The rim pattern was associated with SLE and mixed connective tissue disease. The nucleolar/homogeneous pattern was associated with scleroderma and SLE in remission. ANA titre and staining pattern have limited value in the clinical assessment of rheumatic disease; however, ANA has very high sensitivity for SLE and remains an excellent screening test.

Role of calcitonin gene-related peptide in capsaicin-induced gastric submucosal arteriolar dilation

The response of gastric submucosal arterioles to topical (submucosal) application of calcitonin-gene-related peptide (CGRP) or capsaicin with and without the human CGRP antagonist, hCGRP-(8-37), was studied using in vivo microscopy. CGRP (10(-11) to 10(-8) M) induced dose-dependent dilation. Topical treatment with hCGRP(8-37) (10(-6) M, for 10 min) caused a significant decrease in basal arteriolar diameter from 33 +/- 2 to 27 +/- 2 microns. hCGRP(8-37) did not alter acetylcholine- or adenosine-induced vasodilation but did significantly reduce CGRP 10(-8) M vasodilation from 97.3 +/- 10.1 to 15.9 +/- 4.4% of the maximal response. Topical capsaicin (10(-9) M to 5 x 10(-7) M) induced dose-dependent arteriolar dilation. This vasodilation was markedly attenuated by hCGRP(8-37). Selective ablation of capsaicin-sensitive sensory neurons nearly completely inhibited capsaicin-induced vasodilation, suggesting that this vasodilation is primarily neurogenic in origin. We conclude that 1) topical application of capsaicin stimulates capsaicin-sensitive sensory neurons and induces dose-dependent arteriolar dilation; 2) this vasodilation is mediated in part by CGRP; and 3) CGRP may be involved in modulating the basal tone of gastric resistance vessels.

[Cerebral and carotid arterial radiograms in low tension glaucoma]

Cerebral and carotid arterial radiograms were performed for 22 healthy volunteers, 8 patients with primary open angle glaucoma(POAG), and 10 patients with low tension glaucoma (LTG). Analysis of the Time-Radioactivity Curves suggested that insufficient perfusion of the carotid artery, especially the internal carotid artery, might play an important role in the optic nerve damage of some cases of LTG.

Effects of dextran-induced hyperviscosity on regional blood flow and hemodynamics in dogs

In 10 pentobarbitalized dogs, plasma viscosity (Ep) was raised fourfold while apparent blood viscosity (Ea) increased about twofold by two steps of exchange transfusion of 200 ml of plasma with plasma containing high molecular weight dextran (mol wt 500,000, 20% wt/vol). Elevation of Ea was primarily caused by an increase of Ep but not red cell aggregation. As Ea increased, regional blood flow (by 15-microns microspheres) remained constant in most organs but reduced in the small intestine, spleen, and thyroid gland. Vascular hindrance (Z), which reflects the state of vascular geometry, was calculated as flow resistance per Ea. Among various organs, a reduction in Z was noted in the heart, liver, pancreas, kidney, brain, and adrenal gland. In myocardium, there was a progressive reduction of the endocardial-to-epicardial flow ratio, indicating a less profound vasodilation in endocardium than epicardium. These results indicate that dextran-induced hyperviscosity leads to a compensatory vasodilation in several vital organs thus serving to maintain blood flow and nutrient transport.

Characteristics of natural scenes related to the fractal dimension

Many objects in images of natural scenes are so complex and erratic, that describing them by the familiar models of classical geometry is inadequate. In this paper, we exploit the power of fractal geometry to generate global characteristics of natural scenes. In particular we are concerned with the following two questions: 1) Can we develop a measure which can distinguish between different global backgrounds (e.g., mountains and trees)? and 2) Can we develop a measure that is sensitive to change in distance (or scale)? We present a model based on fractional Brownian motion which will allow us to recover two characteristics related to the fractal dimension from silhouettes. The first characteristic is an estimate of the fractal dimension based on a least squares linear fit. We show that this feature is stable under a variety of real image conditions and use it to distinguish silhouettes of trees from silhouettes of mountains. Next we introduce a new theoretical concept called the average Holder constant and relate it mathematically to the fractal dimension. It is shown that this measurement is sensitive to scale in a predictable manner, and hence, provides the potential for use as a range indicator. Corroborating experimental results are presented.

Effects of blood viscosity on plasma renin activity and renal hemodynamics

The effects of alterations in apparent blood viscosity on renal hemodynamics and plasma renin activity (PRA) were studied in dogs anesthetized with sodium pentobarbital. Blood viscosity was altered isovolemically either by changes in hematocrit (Hct) or by an increase in plasma viscosity (dextran administration). Arterial blood pressure and renal blood flow (RBF) remained relatively constant when apparent blood viscosity was elevated by changes in Hct or plasma viscosity. Thus the hyperviscosity of blood was associated with a decrease of renal vascular hindrance, resulting in an essentially unchanged renal flow resistance. The decrease in renal vascular hindrance may result from renal vasodilation. In hyperviscosity induced with dextran, the increase in PRA correlates linearly with the decrease in renal vascular hindrance, with a coefficient of correlation of 0.968 (P less than 0.005). The increase in PRA that resulted when Hct was raised from 25 to 55% also can be correlated linearly with the decrease in renal vascular hindrance, with a coefficient of correlation of 0.953 (P less than 0.005). These results suggest that the decrease in renal vascular hindrance in response to a rise in apparent blood viscosity leads to an increase in PRA.

Decrease in cerebral blood flow in rats after experimental subarachnoid hemorrhage: a new animal model

There continues to be a need for good animal models of experimental subarachnoid hemorrhage (SAH). The rat would be an ideal subject in which to study SAH since it is inexpensive and easier to use than the larger laboratory animals. The present study was undertaken to determine if alterations of cerebral blood flow could be produced in the rat after experimental SAH, and thereby justify using the rat as a model for further study of SAH. Rats weighing between 450 and 500 grams underwent insertion of a cannula into the cisterna magna at least 5 days prior to physiological testing. One group of rats then received a 0.3 cc injection of fresh autologous arterial blood into the cisterna magna to simulate a SAH. Another group of rats received injection of an equal volume of mock CSF (buffered saline) into the cisterna magna. A third group of rats had no subarachnoid injections. In all three groups, blood flow to the cerebral hemispheres was measured with the labeled microsphere technique. Rats with experimental SAH showed a 40% decrease of cerebral blood flow, whereas rats with saline injections showed only a 15% decrease. Control rats had no changes of cerebral blood flow. These studies demonstrate that the rat is a potential experimental model for investigations into SAH.

Regional cerebral blood flow and oxygen consumption of the canine brain during hemorrhagic hypotension

The sequential changes in systemic and cerebral hemodynamics, systemic and cerebral oxygen transport and consumption rates, and the regional blood flows (measured with 15 micron microspheres) to the cortical and subcortical brain tissues were determined in nine dogs subjected to graded hemorrhage (10 ml/kg X 4 at 15 min intervals). As hemorrhage progressed, both mean arterial pressure and cardiac output decreased progressively. In contrast to the systemic circulation, the mean cerebral blood flow (mCBF) was well maintained by cerebral vasodilation and the cerebral O2 consumption rate (CMRO2) increased during the first three stages of hemorrhage. At 40 ml/kg of hemorrhage, there were significant reduction in mCBF and CMRO2 despite the increase in O2 extraction, suggesting the occurrence of cerebral hypoxia and decompensation of the cerebral circulation. There were remarkable regional variations in the responses of regional cerebral blood flows (rCBF) to hypovolemia, resulting in a significant redistribution of cerebral blood flow. The fractions of cardiac output supplying the diencephalon (thalamus and hypothalamus), the brain stem (pons and medulla oblongata) and the cervical spinal cord increased after hemorrhage up to 40 ml/kg. The redistribution of rCBF favors those areas where neurons related to cardiovascular control are located. These findings have significant implications relating to hemodynamic regulation during hemorrhagic hypotension.

Determination of the partition coefficient of 133xenon between oral tissues and blood in the dog

Ostwald solubility coefficients for 133Xe in plasma (Sp), red blood cells (Sc), and selected oral tissue homogenates (St) obtained from the dog were determined at 4, 20, 27 and 37 degrees C by counting the 133Xe activity of the air phase and the sample (liquid, red cells or tissue) in the same tube following equilibration. The partition coefficient for xenon (lambda, in ml/g) between red cells and plasma (lambda cp) and that between tissues and plasma (lambda tp) were calculated from the measured Sp, Sc and St. The tissue-blood partition coefficients (lambda tb) of oral tissues for 133Xe were then calculated using lambda cp, lambda tp and the haematocrit value. The calculated values of lambda tb at 37 degrees C and 50 per cent haematocrit were 0.650 for the pulp, 0.674 for the tongue, 0.828 for the submandibular gland and 0.881 for the gingiva of the dog. lambda cp increased and lambda tp decreased as the temperature was reduced from 37 to 4 degrees C.

Effects of sphere size and injection site on regional cerebral blood flow measurements

Regional cerebral blood flows and shunting of microspheres with four different sizes (9,12, 16 and 25 microns) into the superior sagittal sinus were determined in twelve dogs. Venous blood was collected from the superior sagittal sinus for 120 min after the injection of microspheres, and the dogs were then sacrificed immediately. Results on blood flow measurements and venous shunting determinations were similar between left ventricular and left atrial injections. Blood flows measured by 12, 16 and 25 microns spheres were comparable in various brain tissues, except the choroid plexus. 9 microns spheres underestimated blood flows in all regions studied: by 13-19 percent in the cerebral cortex, midbrain, brain stem and cerebellum, by 34-42 percent in the cortical white matter, corpus callosum and cervical cord, and by 64-81 percent in pituitary gland and choroid plexus. These results probably reflect regional difference in microvascular architecture. Venous shunting of 9, 12, 16 and 25 microns spheres during a 24 hr period were 23.6 +/- 2.5, 12.6 +/- 1.2, 4.8 +/- 1.4, and 4.0 +/- 1.2 percent (mean +/- SEM), respectively, with respect to the arterial delivery. Although most of the venous shunting occurred during the first 3 min after the injection of microspheres, it continued 3-60 min after the injection. Beyond 60 min, the venous shunting became minimal for 16 and 25 microns spheres, while significant amount of 9 microns spheres continued to appear in sagittal sinus. This time dependent shunting indicates that some microspheres may be transiently trapped in the microcirculation and become gradually dislodged with time. Failure to consider this time dependence may underestimate the shunting of microspheres through the microcirculation.(ABSTRACT TRUNCATED AT 250 WORDS)

Baroreflex control of heart rate in humans during nitroprusside-induced hypotension

The baroreflex control of heart rate was investigated on 10 informed human subjects during light halothane anesthesia (0.3-0.5%, inspired concentration). The relationship of systolic pressure (SP) to the succeeding pulse interval (PI) was evaluated on a beat-to-beat basis during the entire course of sodium nitroprusside (SNP) depressor test. The initial slope of SP-PI plot (dPI/dSP) was used as an index of the sensitivity of baroreflex control of heart rate. Following an injection of SNP (4-6 micrograms/kg), dPI/dt was related directly to dPI/dSP, whereas the latter was inversely correlated with dSP/dt. The recovery of PI lagged behind that of SP, and there was a hysteresislike loop on the SP-PI plot. The time lag of PI recovery and the loop of SP-PI plot were markedly decreased by propranolol treatment and significantly increased by atropine. The slopes of SP-PI plot were significantly decreased by atropine but relatively unaffected by propranolol. These results indicate that SNP-induced hypotension in man during halothane anesthesia is associated with a withdrawal of parasympathetic inhibition and an enhancement of sympathetic activity. The autonomic control of heart rate in response to rapid changes in arterial pressure induced by SNP is dominated by parasympathetic influence; the more persistent sympathetic activity only becomes evident when the parasympathetic influence subsides quickly as the arterial pressure stays relatively constant at a new level. The slope of SP-PI plot (dPI/dSP) and the ratio of dPI/dt to dSP/dt during the decreasing pressure phase of SNP test can be used as indices for the sensitivity of baroreflex control of heart rate.

Bypass blood flow during carotid endarterectomy

The relationship of bypass shunt blood flow to arterial pressure and stump pressure was studied in 12 informed patients undergoing carotid endarterectomy. These patients were anesthetized with halothane plus nitrous oxide. Systemic arterial blood pressure was measured with a radial artery catheter, and stump pressure as well as distal shunt pressure (carotid pressure distal to the shunt) were measured with a 25-gauge needle inserted cephalad to the bypass shunt. From the pressure drop across the bypass shunt, blood viscosity, geometry of the bypass tubing and the use of Poiseullie's law, the shunt blood flow can be calculated. The calculated shunt flow shows a close correlation with the difference between arterial pressure and stump pressure (r = 0.91) as well as with the slope of arterial pressure increase following carotid occlusion (r = 0.82); but it is poorly correlated with the stump pressure. Administration of 100 ml low molecular weight dextran solution does not improve the shunt blood flow, whereas 500 ml low molecular weight dextran significantly decreases blood viscosity. The patency of the carotid artery as assessed by angiogram does not give a proper indication of the need for a bypass shunt. The shunt flow as well as the need of such a shunt might be predicted by the use of the difference of arterial pressure and stump pressure. If the slope of arterial pressure increases rapidly following carotid occlusion, it can also be used to determine the necessity of such a shunt.

Hemoconcentration induced by surface hypothermia in infants

The effects of surface hypothermia (25 degrees C) on arterial hematocrit value (by microcentrifuge) and plasma protein concentration (by refractometry) were studied in infants undergoing surface cooling for cardiac operations. To analyze in detail the mechanisms leading to the observed changes in patients, we performed parallel studies on normal dogs and permanently splenectomized dogs. In these dogs, measurements were also made of plasma volume (by 125I-albumin) and red cell volume (by 51Cr-erythrocytes). Arterial hematocrit value increased progressively during surface cooling in infants. Assuming that red cell volume remained constant and that the ratio of whole body red cell percentage to arterial hematocrit value during surface cooling in infants as in splenectomized dogs, we estimated percent changes in plasma volume in infants from arterial hematocrit data. The computed plasma volume decreased progressively as the body temperature was decreased. Since plasma protein concentration remained constant, the loss of plasma volume suggested a sequestration of whole plasma in portions of the circulatory bed and/or an extravasation of whole plasma into the interstitial space.

Effects of hematocrit variations on regional hemodynamics and oxygen transport in the dog

The responses of alterations in regional hemodynamics and oxygen transport rate to hematocrit (Hct) were studied in 20 pentobarbitalized dogs. Hemodilution was carried out by isovolemic exchange with plasma in 12 dogs and the hemoconcentration with packed cells in 8 dogs. The cardiac output and regional blood flows were determined with the microsphere technique. In hemodilution, the increases of blood flow to the myocardium and the brain were out of proportion to the increase of cardiac output; the oxygen supply to the myocardium remained unchanged while that to the brain decreased only slightly. In hemoconcentration, vasodilation occurred in the myocardium and the brain to maintain constant oxygen supply. Splenic vessels had marked vasoconstriction with Hct alteration in either direction. Blood vessels in the liver, intestine, and kidney responded with a milder vasoconstriction and maintained a constant oxygen supply between Hct of 30-55%. Therefore, during Hct alteration, redistribution of blood flow to myocardium and brain occurred. The optimal Hct range for constant oxygen supply was different among various organs.

Determinations of blood flow and shunting of 9- and 15-micrometer spheres in regional beds

In 17 pentobarbitalized dogs, the shunting of 15-micrometer and 9-micrometer microspheres was studied in the brain, myocardium, kidney, intestine, and lung. The veins of these organs were catheterized for constant blood withdrawal for 2 min by direct venipuncture. The ratio of microsphere radioactivity in the venous blood to that in the arterial blood gave the shunting of microspheres by the venous sampling technique. The 15-micrometer microspheres showed 2% or less shunting for all organs studied, whereas the 9-micrometer microspheres had shunting ranging from 3% in the coronary sinus to 24% in the portal vein. The shunting of 9-micrometer microspheres was also calculated from direct tissue counting, where the 15-micrometer spheres were considered to be completely entrapped. The results of direct tissue counting indicate that the 2-min venous sampling underestimates microsphere shunting. CO2 administration increased significantly the shunting of 9-micrometer spheres, whereas the shunting of 15-micrometer spheres determined by venous sampling remained less than 2%. Consideration of shunting indicates that the 15-micrometer microspheres might be more appropriate for regional organ blood flow measurements, including the myocardium.

Hemodynamic functions and blood viscosity in surface hypothermia

Hemodynamic functions and blood viscosity changes in hypothermia (core approximately 25 degrees C) were studied in 14 pentobarbital-anesthetized dogs subjected to surface cooling. The viscosity of blood (eta B) increased progressively to 173% of that at 37 degrees C when body temperature was lowered to 25 degrees C. The increase in blood viscosity was caused by: a) the direct effect of low temperature on plasma viscosity, b) hemoconcentration as a result of plasma loss, and c) the low-flow (low-shear) state induced by hypothermia. A larger portion of the increased viscosity was caused by the low-flow state in hypothermia. The systemic flow resistance (SFR) increased to 271% of control, and this was attributable about equally to the increases in blood viscosity and systemic vascular hindrance (SFR/eta B). Similarly, the viscosity of blood contributed significantly to raising the pulmonary flow resistance. The relative constancy of mixed venous O2 saturation suggests that the cardiac output at low body temperature is generally adequate to meet the metabolic needs.

Plasma volume, red cell volume, and thoracic duct lymph flow in hypothermia

The effects of hypothermia on plasma volume (125I-albumin), red blood cell volume (51 Cr-RBC), and capillary permeability (thoracic duct lymph flow and protein concentration) were determined on dogs anesthetized with pentobarbital, paralyzed with succinylcholine, and mechanically ventilated. Red blood cell volume and plasma protein concentration did not change significantly after cooling. Reductions in plasma volume and total plasma proteins indicate that whole plasma was excluded from the effective circulating blood volume. Except for a lesser increase in hematocrit, chronically splenectomized dogs showed essentially the same changes as normal dogs in response to hypothermia. Following application of ice bags, there was a biphasic response in lymph flow. The early increase in lymph flow accompanying a slight decrease in plasma volume was attributable to transcapillary fluid loss into interstitial space, probably due to cold-induced sympathetic activity. The later decrease in lymph flow in hypothermia resulted from a decrease of lymph production secondary to a decrease in available capillary diffusion area. This decrease in lymph flows and the continued reduction in plasma volume suggest an intravascular sequestration of whole plasma.