Therapeutic Advantage of Recombinant Human Plasminogen Activator in Endocarditis: Evidence from Experiments in Rabbits

In infective endocarditis vegetations are stabilized by fibrin. To learn if fibrin digestion would be therapeutic, experimental endocarditis was induced in rabbits by inoculation with a platelet-aggregating strain (Agg+) of Streptococcus sanguis and treated with recombinant tissue plasminogen activator (rt-PA), rt-PA with penicillin, or penicillin alone. Control rabbits were inoculated with saline. All treatments of Agg+ endocarditis reduced the mass of valvular vegetations and clinical signs of endocarditis, including the frequency of left axis deviation and heart ischemia. rt-PA with penicillin was more effective than penicillin or rt-PA alone, reducing the mass of vegetations and clinical signs to that of saline controls. Within 50 min, rt-PA cleared 5-fold more 111Indium-labelled platelets from the heart than untreated rabbits and 1.4-fold more after 3 days. Combined with penicillin, thrombolytic therapy for human endocarditis should be reconsidered.

[Punctate inner choroidopathy - Improvement in vision after anti-VEGF and photodynamic therapy. An 18-month follow-up control]

Punctate inner choroidopathy (PIC) is a rare disease which seems to have an inflammatory origin. Treatment is symptom-oriented and the development of choroidal neovascularization (CNV). If CNV is present the trend is towards the use of anti-VEGF (vascular endothelial growth factor) therapy. Oral therapy with steroids should be initially attempted.

[Differential diagnosis in visual field defects of glaucoma patients]

In both cases optic disc neuropathy with perimetry defects and loss of vision is caused by a cerebral tumour. The progression of optic damage was stopped by resection of the tumor in both patients. We recommend the performance of a radiological examination in patients with visual field defects if the intraocular pressure is normal and thus glaucoma may not be the cause of the defects.

Augeninnendruckmessungen mit dem Selbsttonometer Proview® im Vergleich zur Goldmann-Applanationstonometrie bei Gesunden und Glaukompatienten

BACKGROUND

The aim of this study was to compare the results of intraocular pressure (IOP) measurements obtained using the pressure phosphene tonometer Proview with those from Goldmann applanation tonometer (GAT) in normal and glaucomatous eyes.

PATIENTS AND METHODS

The IOP in 150 eyes of 62 healthy volunteers and 88 patients with glaucoma or ocular hypertension was measured prospectively in a sitting position. After being trained to use the Proview device, Goldmann applanation tonometry was performed first. Then the patient took a reading with the Proview self-tonometer.

RESULTS

For all investigated eyes the measurements with the Proview were on average 5.5 mmHg higher than those by GAT. Only 34 % of the readings from the two devices were within a difference range of +/- 3 mmHg. On comparing the group of glaucomatous patients with slight visual field defects with the group of healthy subjects and patients with ocular hypertension without visual field defects we determined almost the same mean difference between the Proview and GAT (mean difference in the group with visual field defects = 4.7 +/- 4.1 mmHg; without defects = 4.8 +/- 2.9 mmHg).

CONCLUSIONS

The tonometer Proview did not show a close agreement to GAT. Therefore, the PPT does not offer an alternative method for measuring IOP. We do not recommend the Proview for self-tonometry at home or for clinical management of patients with glaucoma. Slight visual field defects seem to have no influence on intraocular pressure measurement with the self-tonometer.

Intermittierender ziliarer Block durch Hämodialyse

We report the case of a patient who experienced recurrent elevations of intraocular pressure during haemodialysis. We measured a rise in intraocular pressure of 10-12 mmHg after dialysis. The lens showed intumescence, and a ciliary block was detected by means of Orbscan II. Within 6 h findings had normalized. Changes in serum osmolarity due to haemodialysis may result in fluid shifts between different compartments. Decrease of serum osmolarity during dialysis may lead to lens swelling and thus cause a ciliary block. This may end with regression of the lens swelling.

Anti-fibrin antibody binding in valvular vegetations and kidney lesions during experimental endocarditis

In Streptococcus sanguinis (sanguis) induced experimental endocarditis, we sought evidence that the development of aortic valvular vegetation depends on the availability of fibrin. Endocarditis was induced in New Zealand white rabbits by catheter placement into the left ventricle and inoculation of the bacteria. Fibrin was localized in the developing vegetation with 99mTechnetium (Tc)-labeled anti-fibrin antibody one or three days later. When rabbit anti-fibrin antibody was given intravenously on day 1, the mass of aortic valvular vegetation was significantly reduced at day 3; infusion of non-specific rabbit IgG showed no effect. The 99mTc-labeled anti-fibrin antibody also labeled kidneys that showed macroscopic subcapsular hemorrhage. To learn if the deposition of fibrin in the kidneys was a consequence of endocarditis required a comparison of farm-bred and specific pathogen-free rabbits before and after the induction of endocarditis. Before induction, the kidneys of farm-bred rabbits were labeled, but specific pathogen-free rabbits were free of labeling and signs of macroscopic hemorrhage. After 3 days of endocarditis, kidneys of 10 of 14 specific pathogen-free rabbits labeled with 99mTc-labeled anti-fibrin antibody and showed hemorrhage. Kidney lesions were suggested to be a frequent sequellae of S. sanguinis infective endocarditis. For the first time, fibrin was shown to be required for the continued development of aortic valvular vegetations.

Streptococcal reporter gene-fusion vector for identification of in vivo expressed genes

To study streptococcal genes that are specifically induced in the host during endocarditis, we have developed a novel plasmid for use in in vivo expression technology (IVET). This IVET uses an integration plasmid, pAK36, that carries dual (amy-cat) reporter genes. A gene-fusion strain library was constructed with the plasmid randomly inserted into the chromosome of Streptococcus gordonii V288 by insertion-duplication. The library was inoculated intravenously into a rabbit that had been prepared for experimental endocarditis. Beginning 6 h after the inoculation, the rabbit was given chloramphenicol (Cm) intravenously twice a day to a final serum level of 5 microg/ml and was euthanized 3 days later. The aortic valve vegetations containing Cm(R) S. gordonii clones were cultured. Colonies were screened in vitro for negative amylase activity and sensitivity to Cm. Forty-eight such colonies showed 13 different insertion patterns when Southern hybridization blots were probed with labeled pAK36. For each of the 13 isolates, the gene fragment proximal to the insertion of the reporter amy-cat was cloned, and its nucleotide sequence was determined. Functions of these genes were inferred by their homology to known genes. Therefore, this novel IVET vector can be useful for identification of in vivo induced genes in S. gordonii and other streptococcal species.

Streptococcus sanguis-induced platelet clotting in rabbits and hemodynamic and cardiopulmonary consequences

By mimicking hemostatic structural domains of collagen, Streptococcus sanguis (aggregation-positive phenotype; Agg+) induces platelets to aggregate in vitro. To test the hypothesis that aggregation occurs in vivo, S. sanguis (Agg+ or Agg- suspension) was infused intravenously into rabbits. The extent of hemodynamic and cardiopulmonary changes and the fate of circulating platelets were Agg+ strain dose dependent. Within 45 to 50 s of the start of infusion, 40 x 10(8) CFU of the Agg+ strain caused increased blood pressure. Thirty seconds after infusion, other changes occurred. Intermittent electrocardiographic abnormalities (13 of 15 rabbits), ST-segment depression (10 of 15 rabbits), and preventricular contractions (7 of 15 rabbits) manifested at 3 to 7 min, with frequencies dose dependent. Respiratory rate and cardiac contractility increased during this phase. Blood catecholamine concentration, thrombocytopenia, accumulation of 111Indium-labeled platelets in the lungs, and ventricular axis deviation also showed dose dependency. Rabbits were unaffected by inoculation of an Agg- strain. Therefore, Agg+ S. sanguis induced platelet aggregation in vitro. Platelet clots caused hemodynamic changes, acute pulmonary hypertension, and cardiac abnormalities, including ischemia.

Gender stereotypes: a bias against men

In a class on the psychology of male roles, 38 undergraduates (18 men, 20 women) participated in an activity designed to assess gender stereotypes. A chi-square analysis revealed that participants produced significantly more negative stereotypes for men than for women. These results, consistent with crosscultural findings, are discussed in terms of methodological issues and the differential socialization of men and women.

Host-pathogen interactions in bacterial endocarditis: streptococcal virulence in the host

To identify streptococcal genes that are expressed during experimental endocarditis, we developed a promoter-less dual reporter gene-fusion (amy, cat) plasmid, pAK36. Chromosomal DNA from S. gordonii V288 was digested with Sau3A1. The resulting fragments were ligated into pAK36. Following transformation into S. gordonii, the library of random gene fusion clones was inoculated into a rabbit to induce experimental endocarditis. Chloramphenicol treatment effected positive selection. Upon euthanization of the rabbits, the valvular vegetations were excised in a sterile field. Surviving clones were isolated and screened in vitro for chloramphenicol sensitivity and negative amylase activity. From the 48 randomly picked, double-negative clones, DNA was isolated and analyzed by Southern hybridization with labeled pAK36 probe. Different insertion patterns were identified, suggesting that no fewer than 13 S. gordonii genes were induced. Therefore, S. gordonii genes are induced during experimental endocarditis, which may contribute to virulence.

Validation of the doubly labeled water method in bald eagles (Haliaeetus leucocephalus) and a comparison of two equations for the calculation of energy expenditure

We validated the doubly labeled water (DLW) technique for measurement of energy expenditure in bald eagles (Haliaeetus leucocephalus) in captivity by simultaneously measuring metabolizable energy intake in a feeding trial. We calculated CO2 production using two equations, one typically used by animal ecologists (the "one-pool" equation) and the other typically used by human nutritionists (the "two-pool" equation). Metabolizable energy intake, as determined by feeding trials, for two adult eagles eating rats averaged 1,160 +/- 89 kJ d-1 and for four nestlings eating fish averaged 2,124 +/- 40 kJ d-1. Energy expenditure measured from DLW turnover using the one-pool equation averaged 2.2% +/- 7.1% higher than metabolizable energy intake measured by feeding trials (not significantly different, P > 0.50), but when the two-pool equation was used, energy expenditure measured with DLW averaged 17.7% +/- 6.7% lower than metabolizable energy intake measured by feeding trials (significantly different, 0.025 < P < 0.05). Thus, the use of the DLW technique with CO2 production calculated by the one-pool equation was validated for bald eagles.

Effects of oral flora on platelets: possible consequences in cardiovascular disease

During episodes of dental bacteremia, viridans group streptococci encounter platelets. Among these microorganisms, certain Streptococcus sanguis induce human and rabbit platelets to aggregate in vitro. In experimental rabbits, circulating streptococci induced platelets to aggregate, triggering the accumulation of platelets and fibrin into the heart valve vegetations of endocarditis. At necropsy, affected rabbit hearts showed ischemic areas. We therefore hypothesized that circulating S. sanguis might cause coronary thrombosis and signs of myocardial infarction (MI). Signs of MI were monitored in rabbits after infusion with platelet-aggregating doses of 4 to 40 x 10(9) cells of S. sanguis 133-79. Infusion resulted in dose-dependent changes in electrocardiograms, blood pressure, heart rate, and cardiac contractility. These changes were consistent with the occurrence of MI. Platelets isolated from hyperlipidemic rabbits showed an accelerated in vitro aggregation response to strain 133-79. Cultured from immunosuppressed children with septic shock and signs of disseminated intravascular coagulation, more than 60% of isolates of viridans streptococci induced platelet aggregation when tested in vitro. The data are consistent with a thrombogenic role for S. sanguis in human disease, contributing to the development of the vegetative lesion in infective endocarditis and a thrombotic mechanism to explain the additional contributed risk of periodontitis to MI.

Residues of organochlorines in mallards and blue-winged teal collected in Colombia and Wisconsin, 1984-1989

We compared the seasonal concentrations of 12 organochlorine (OC) compounds in samples of breast muscle, associated skin, and subcutaneous fat of blue-winged teal (Anas discors) collected in Ciénaga Grande de Santa Marta, Colombia (1987-1988), and of mallards (Anas platyrhynchos) and blue-winged teal collected in Wisconsin (1984-1989). Although these species have similar feeding habits and overlapping breeding distributions, their winter ranges differ markedly. Most blue-winged teal winter in the Neotropics, whereas most mallards remain in the temperate regions of North America. A seasonal comparison of OC exposure in these species may help determine the geographic origins of contamination. All examined OCs were found to be below concentrations known to affect reproduction in waterfowl. DDE was most often detected in blue-winged teal and PCBs, in mallards. DDE exposure may have predominantly occurred outside of Wisconsin. The DDE concentration in blue-winged teal samples collected in Wisconsin in the spring (GM=0.406 microg/g) were greater (P<0.001) than in the fall (GM=0. 033 microg/g) and greater than the concentrations in mallard samples from the spring (GM=0.058 microg/g; P<0.001). Ciénaga Grande, however, was not a source of DDE contamination. The DDE concentrations in blue-winged teal samples from Ciénaga Grande did not differ between the spring (GM=0.037 microg/g) and the fall (GM=0. 039 microg/g) and were lower (P<0.001) than the concentration in blue-winged teal samples from Wisconsin in the spring. In contrast, PCB contamination seemed to have occurred in Wisconsin and affected mostly mallards. PCBs were not detected in the samples from Colombia and were detected in only five (8.3%) of the blue-winged teal samples from Wisconsin (GM=0.025 microg/g), however, those compounds were detected in 47% of the mallard samples collected in Wisconsin (GM=0.272 microg/g). DDE and PCB concentrations were greater (P=0.0) in mallard samples collected from wetlands adjacent to Lake Michigan than in samples from inland wetlands.

Therapeutic advantage of recombinant human plasminogen activator in endocarditis: evidence from experiments in rabbits

In infective endocarditis vegetations are stabilized by fibrin. To learn if fibrin digestion would be therapeutic, experimental endocarditis was induced in rabbits by inoculation with a platelet-aggregating strain (Agg+) of Streptococcus sanguis and treated with recombinant tissue plasminogen activator (rt-PA), rt-PA with penicillin, or penicillin alone. Control rabbits were inoculated with saline. All treatments of Agg+ endocarditis reduced the mass of valvular vegetations and clinical signs of endocarditis, including the frequency of left axis deviation and heart ischemia. rt-PA with penicillin was more effective than penicillin or rt-PA alone, reducing the mass of vegetations and clinical signs to that of saline controls. Within 50 min, rt-PA cleared 5-fold more 111Indium-labelled platelets from the heart than untreated rabbits and 1.4-fold more after 3 days. Combined with penicillin, thrombolytic therapy for human endocarditis should be reconsidered.

Orf virus infection in pregnancy

Orf virus infection is endemic among sheep and goats, and can occur in humans who handle these animals. Orf virus infection in humans causes a characteristic skin lesion, and systemic symptoms can occur. Very little is known about Orf virus infection in human pregnancy. A case of Orf virus infection, with onset at 33 weeks gestation, is presented. There were no pathological findings in the infant born at term, or in the placenta.

The platelet interactivity phenotype of Streptococcus sanguis influences the course of experimental endocarditis

A strain of Streptococcus sanguis that induced rabbit platelets to aggregate in vitro (Agg+ phenotype) was hypothesized to be a more virulent pathogen than an Agg- strain in experimental endocarditis in rabbits. A left ventricular catheter was implanted, and then an Agg+ or Agg- strain was inoculated intravenously. Vegetations formed on the aortic semilunar valves but were unaffected by the duration of implantation of the catheter. Vegetations enlarged by accumulating platelets and their mass increased directly with the duration of endocarditis. Inoculation of the Agg+ strain consistently caused endocarditis with significantly larger vegetations, a more severe clinical course (including febrile episodes, hematological changes, and signs of myocardial ischemia), more gross lesions in major organs, and greater mortality than inoculation with the Agg- strain, saline, or the Agg+ strain pretreated with monospecific rabbit immunoglobulin G or Fab fragments against its platelet aggregation-associated protein (PAAP; class II). In experimental endocarditis, PAAP expressed by Agg+ S. sanguis appeared to be an important virulence factor.

The kinetics of diastereomeric amino acids with o-phthaldialdehyde

The kinetics of the reaction of the amino acid epimers L-isoleucine, D-allo-isoleucine, L-threonine, and D-allo-threonine with o-phthaldialdehyde and mercaptoethanol were determined at 25 degrees C. L-Isoleucine reacts faster than its D-epimer whereas L-threonine reacts slightly slower than its D-epimer. In the case of isoleucine, the consequence can be an allo/iso ratio which in the worst case is 25% too low if these amino acids are quantified by liquid chromatography and o-phthaldialdehyde fluorescence detection. The effect on dating of fossils by amino acid racemization is discussed.

Umbilical blood pressures and utero-placental blood flow in spontaneously hypertensive rats

Some substrains of spontaneously hypertensive rats (SHR) are hypertensive at birth, suggesting the possibility of pre-natal hypertension. Fetal haemodynamics are sensitive to utero-placental blood flow changes. Thus, we used micropuncture to measure umbilical vein blood pressure (BP) in SHR and Wistar-Kyoto rats (WKY) at 18 and 20 days post-conception. We determined utero-placental blood flow (UPBF) at 17 and 20 days post-conception by the microsphere method. Results showed that SHR fetuses were hypertensive only at 20 days. Fetal heart:body weight ratio was higher in SHR, decreased with age and was not associated with BP or heart rate. Utero-placental weight was not affected by either age or strain. However, utero-placental blood flow was low in SHR at 20 days. Thus, in SHR pre-natal hypertension occurs between 18 and 20 days post-conception; pre-natal hypertension is associated with low utero-placental blood flow.

Mechanisms of recovery from aphasia: evidence from serial xenon 133 cerebral blood flow studies

In 21 patients who suffered aphasia resulting from left hemisphere ischemic infarction, the xenon 133 inhalation cerebral blood flow technique was used to measure cerebral blood flow within 3 months and 5 to 12 months after stroke. In addition to baseline measurements, cerebral blood flow measurements were also carried out while the patients were performing purposeful listening. In patients with incomplete recovery of comprehension and left posterior temporal-inferior parietal lesions, greater cerebral blood flow occurred with listening in the right inferior frontal region in the late studies than in the early studies. In patients with nearly complete recovery of comprehension and without left posterior temporal-inferior parietal lesions, early listening studies showed diffuse right hemisphere increases in cerebral blood flow. Later listening studies in this latter patient group showed greater cerebral blood flow in the left posterior temporal-inferior parietal region. The study provides evidence for participation of the right hemisphere in language comprehension in recovering aphasics, and for later return of function in left hemisphere regions that may have been functionally impaired early during recovery.

Flap design and the LeFort III osteotomy: blood flow investigation

The effect on local blood flow of flap design in a LeFort III osteotomy was examined in this study. The radioactive microsphere technique was used to make serial flow determinations in two groups of macaque monkeys. The use of seven skin and mucosal incisions was compared with a coronal flap procedure. Significant blood flow reductions to the midface segment where measured when a coronal incision was the sole access in performance of the osteotomies. The findings indicate that the multiple incision approach is more biologically sound than the coronal incision approach in the LeFort III osteotomy. Important information about the surgical techniques can be determined from the data and applied to a more successful performance of the LeFort III osteotomy.

Regional cerebral blood flow correlates of auditory processing

To study the regional cerebral blood flow (rCBF) correlates of auditory processing, we performed rCBF measurements in young, normal right-handed volunteers engaged in listening tasks. Using the xenon Xe 133 inhalation technique, rCBF was measured in 11 regions in each hemisphere. Compared with a baseline condition, significant rCBF increases in the left posterior Sylvian regions were associated with both verbal phonologic processing and nonverbal acoustic processing. Verbal semantic processing was associated with unilateral increased rCBF in the posterior Sylvian region contralateral to the hand used for response signaling. Comparison of rCBF from homologous regions of the two hemispheres also confirmed a clear difference between the rhyme detection and meaning detection tasks, with the former strongly lateralized to the left hemisphere. Thus, changes in rCBF were related to the nature of the listening task.

Evaluation of local blood flow after total maxillary osteotomy

The radioactive microsphere method was used to quantitate blood flow to selected maxillary tissues before and during left-side cervical sympathetic stimulation in a group of 15 macaque monkeys, nine of which received Le Fort osteotomies. The sympathetic system to regulate blood flow appears to have been modified and has not returned to its normal regulatory status six weeks after the operation.

Tissue pertechnetate and iodinated contrast material in ischemic stroke

Isotope uptake during static radionuclide scanning and contrast enhancement during CT scanning, which may result from similar pathophysiologic mechanisms after ischemic infarction, were investigated in an animal model. Infarction was produced by transorbital occlusion of the middle cerebral artery in cats killed one, 2, 4, 8, or 16 days later. Sodium pertechnetate containing technetium-99m and 30% methylglucamine iothalamate labeled with I-125 were administered intravenously 60 and 15 min respectively prior to sacrifice. A coronal section through the infarct was parceled into 30 portions which were assayed for concentration of each isotope. Adjacent brain was prepared for histopathologic correlation. Concentrations of the 2 materials were highest in infarcted brain at 4 and 8 days. Strong positive correlation was found between tissue concentrations of the 2 materials in all brain samples. Elevated tissue levels correlated with necrosis, macrophage infiltration, and vascular hyperplasia. The results support the probability that radionuclide scan positivity and CT contrast enhancement reflect the same pathophysiologic development, probably extravasation of the respective labels, after ischemic stroke.

Blood flow and oxygen consumption in steroid-treated dental pulps

This study examined pulpal blood flow and oxygen consumption by the dental pulps of dogs. Blood flow was measured by the radioactive microsphere method and oxygen uptake was determined by the indirect Warburg approach. These variables were assessed 2 days after the canine teeth had been exposed and treated with either a cotton pellet impregnated with 1 per cent prednisolone or normal saline. The analysis indicated that the pulpal blood flow as well as the oxygen consumption did not differ between the steriod-treated tooth and the corresponding saline-treated tooth in the same jaw.

Thorotrast induced adhesive arachnoiditis associated with meningioma and schwannoma

Adhesive arachnoiditis, a meningioma and a schwannoma were found at autopsy in a 56 year old man who had undergone Thorotrast myelography 33 years previously. Thorotrast was demonstrated in tissue sections by transmission and scanning electron microscopy, radioautography, and x-ray spectrometry.

Quantitation of blood flow after anterior maxillary osteotomy: investigation of three surgical approaches

The radioactive microsphere method was used to quantitate preoperative and postoperative blood flows in macaque monkeys when three different surgical approaches for anterior maxillary osteotomy were performed. Despite distinct variations in flap designs among the experimental groups, preoperative and postoperative determinations of blood flow were essentially unchanged. Results of the study suggest that a palatal, labial, or combined mucoperiosteal pedicle should be adequate to preserve the flow of blood to tissues in the osteotomized segment.

Quantification of pulpal blood flow in developing teeth of dogs

Pulpal blood flow was determined in 32 dogs ranging in age from 6 weeks to 18 months by the isotope fractionation method incorporating diffusible and nondiffusible tracers. Dogs were placed into selected age groups by the developmental status of the canine teeth. For the teeth sampled, the maxillary first, second, and third incisors along with the canines and first molars, pulpal blood flow was determined to be not different in teeth at various developmental stages. For some dental pulps, alveolar mucosa, and bone, the tracers were not determining equivalent blood flows. Because of incomplete trapping of the 7- to 10 mu microspheres and the flow limitation of 86Rb, the 15 mu spheres would appear to be a reliable indicator of "total" blood flow to pulpal tissues. However, in alveolar mucosa and bone, and 15 mu microspheres may not be completely trapped and thus, may underestimate blood flow to these tissues. Within the age range of these dogs, tissue blood flow was not dependent upon the stages of oral development.

Tonometric measurement of dental pulpal and mandibular marrow blood pressures

Dental pulpal and mandibular marrow vascular pressures were studied with a tonometric method under conditions of autoperfusion and step flow controlled perfusion. The tonometric pulpal and marrow pressures averaged 17 +/- 5 mm Hg and 20 +/- 6 mm Hg, respectively. The venous end pressure was 16 +/- 8 mm Hg at a perfusion pressure of 156 +/- 28 mm Hg. The tonometric pulpal pressures were lower and were less variable than the comparable canulation pulpal pressures.

Sympathetic regulation of cephalic blood flow

Blood flow to bilateral tissues (cranial and extracranial) was studied by means of the particle distribution method in two groups of anesthetized dogs (five using 25-mu radioactive microspheres, six using 15-mu microspheres) and five anesthetized stumptail Macaques monkeys (8-mj spheres) during unilateral sympathetic stimulation. The stimulatory parameters were adjusted to produce maximum pupillary dilatation. In the five dogs hemispheric and regional cerebral blood flow decreased but not significantly. Flow to the extracranial tissues decreased 82%. Hemispheric brain blood flow averaged 0.70 ml/min/gm for Paco2 of 40 mm Hg. In the six dogs sympathetic stimulation did not significantly decrease cerebral blood flow but decreased flow to extracranial tissues (72.3%). At an average Paco2 of 33.2 mm Hg, hemispheric blood flow to the unstimulated side averaged 0.51 ml/min/gm. In the five monkeys findings were essentially the same as those observed in the dogs. The hemispheric blood flow averaged 0.36 ml/min/gm on the nonstimulated side for an average Paco2 of 36.6 mm Hg. Under the conditions studied, electrical stimulation of the cervical sympathetic nerves does not appear to modify regional or total brain blood flow in dogs and Macaques monkeys. The vascular response in oral and other extracranial tissues is very dramatic, however.

Blood flow changes after sagittal split of the mandibular ramus

Blood flows to various cephalic tissues were determined by the microsphere method before and after unilateral sagittal split of the mandible in macaque monkeys. Significant blood flow decreases were found in certain bony regions of the osteotomized mandible while blood flow to the masseter and medial pterygoid muscles on theosteotomized side was significantly increased. Judicious stripping of the mucoperiosteum and pterygomassteric sling may be an important consideration when planning the sagittal split approach to correct certain mandibular anomalies.

Quantitation of blood flow after Le Fort I osteotomy

Le Fort I maxillary osteotomies were performed on ten macaque monkeys. The particle distribution method (nondiffusible radioactive microspheres) was used to quantitate local blood flow before and after surgery. Significant reduction in blood flow to the osteotomized maxillary segment was noted in those animals (group S) where the descending palatine vessels were transected. Those animals in which the vascular pedicle was intact (group I) showed decreased blood flow to the attached gingiva and alveolar bone, but palatal tissue blood flow was unchanged or increased. The results reinforce the precept of the importance of maintaining an adequate nutrient pedicle when performing orthognathic surgical procedures.

Fibroelastic hamartoma (fibroma) of the heart

Approximately 70 cardiac fibromas (fibroelastic hamartomas) have been reported in the literature and at least 15 have been successfully excised. However there is no well-documented ultrastructural study of these lesions. A successfully excised cardiac fibroma (FEH) was studied by light and elctron microscopy. The tumor was composed mainly of fibroblasts admixed with bundles of collagen and elastic fibers. No muscle fibers were demonstrated in the central region of the tumor either by light or electron microscopy. Mast cells were occasionally present. The lack of encapsulation enabled fibroblasts with collagen and elastic fibers to extend between groups of myocardial fibers at the periphery of the tumor. Within these myocardial fibers ultrastructural changes were limited to the mitochondria and myofibrillar structure.

Blood flow changes after orthognathic surgery: maxillary and mandibular subapical osteotomy

Subapical osteotomies were performed in the left quadrant of the mandibles and maxillas of five dogs and six monkeys. Two indirect methods, the isotope fractionation (diffusible tracer) and particle distribution (nondiffusible tracer--15mu microspheres) were used to quantitate local blood flow. To examine the effect of the surgery, blood flows in the alveolar bone, mucosa, and dental pulp of the segmented left quadrant and the corresponding tissues in the right quadrant were calculated and compared. It was assumed that the blood flows to the nonoperated right quadrant could serve as the controls to those observed in the osteotomized segment. The fractional decrease in blood flows to tissues in the operated sides were similar in both experimental animals. The decrease was largest in the dental pulp, ranging from 54% to 82% on the average, and least for the mucosal tissue, ranging from 18% to 40%. Blood flows decreased by 48% to 74%, on the average, in the alveolar bone. In some animals, blood flow to mucosal tissue that served as the pedicle was actually greater than the blood flow in the corresponding tissue on the right side. After surgery, the cardiac output in the dogs averaged about 156 ml/min/kg as calculated from both the diffusible and nondiffusible data. In the monkeys in which only the microspheres were injected, the cardiac output averaged 99 ml/min/kg. The arterial blood pressure dropped 8 to 13 mm Hg on the average (dog, 108 to 100 mm Hg; monkeys, 94 to 81 mm Hg). The heart rate also decreased slightly in dogs, 158 to 139 beats/min on the average; however, it increased slightly after the surgery in the monkeys, 144 to 161 beats/min. Blood losses during surgery were replaced wtih lactated Ringer's solution and the transient decreases in blood pressure of about 20 to 35 mm Hg were not sufficient to produce any shut down of renal blood flow.

Distribution of cardiac output in dogs during intravenous infusion of betahistine

Cardiac output (CO), arterial blood pressure (ABP), heart rate (HR), blood gases and blood flow (BF) to the brain, heart, kidney and skeletal muscles and other cephalic tissues in five dogs were studied before and at 30 minutes of betahistine infusion (0.12 to 0.2 mg per minute per kilogram). The particle distribution method using radioactive labeled 141Ce (15 mu) and 85Sr (15 mu) microspheres was utilized to quantitate and assess BF and CO. In the five dogs, the increase in CO averaged 20.8%, ABP remained constant, and HR increased in all but one exception where it decreased slightly concomitant with a decrease in Paco2. Brain BF increased (+ 29.6%) in the dogs whose Paco2 reamined constant. The BF increased to the heart (25.4%) and skeletal muslce (80%), while BF to the kidney and other tissues did not change. The change in HR appears to account for the change in CO. The dilating effect of betahistine on blood vessels, in the skeletal muscle, brain and heart could reduce peripheral resistance and decreace ABP. Thus, the increase in HR may be mediated through baroreceptor mechanisms rather than by a direct effect of betahistine. In addition, a decrease in Paco2, is more effective for decreasing cerebral BF than betahistine is for increasing blood flow.

Blood flow in the central and peripheral nervous system of dogs using a particle distribution method

In this study known activities of 85 Sr and 169 Yb-labeled microspheres were injected sequentially into the left ventricle of anesthetized dogs. Cardiac output was determined before and after each microsphere injection. Blood flow to brain, brain stem, spinal cord, and sciatic nerve was measured from fractional distribution of the microspheres in the tissue samples. Both blood flow and fractional uptake value tended to be higher for brain and brain stem than for spinal cord or sciatic nerve. Increases in arterial Pa CO CO2 were positively correlated with increases in blood flow to both central and peripheral nervous tissue. Initial trapping of the labeled microspheres seems to have little effect on subsequent flow to the tissue capillary bed. It appears that the particle distribution technique may provide a reasonable estimate of blood flow in central and peripheral nervous tissue of dogs.

Distributionoof cardiac output to oral tissues in dogs

Isotope fractionation and particle distribution methods were used in conjunction to quantitate blood flow in the oral mucosa, alveolar bone, tongue, masseter muscle, and dental pulp. Infiltration of epinephrine in lidocaine ( Xylocaine) and lidocaine alone and inhalation of 5% CO2 provided experimental conditions to alter flow in some tissues.