Electromyographic activity of the jaw-closing muscles before and after unilateral coronoidectomy performed on a patient with coronoid hyperplasia: a case study

There have been few reports analyzing the activity of the jaw-closing muscles after coronoidectomy performed on a patient with coronoid hyperplasia. This paper presents a case study using electromyograms (EMGs) to evaluate the effects of unilateral coronoidectomy on the activity of masseter and temporal muscles. The patient was a 25-year-old male whose maximal range of jaw opening was 24 mm. After coronoidectomy of the left region, the range improved to 43 mm. EMGs were recorded in the center of the masseter muscles and the anterior part of the temporal muscles during gum chewing. Preoperatively, no abnormal EMG activity was observed. Eight months after surgery, increase in the ratio of the bilateral temporal muscle activity and a decrease in the ratio of the right masseter muscle activity were observed, and the proportion of activity of jaw closing muscles was out of the normal range. Eighteen months after surgery, there was slight return to the preoperative EMG activity. It was concluded that unilateral coronoidectomy could result in EMG changes of masseter and temporal muscles with a gradual return.

[Usefulness of cytology applied simultaneously to frozen section at rapid intraoperative diagnosis of intracranial tumors]

We discussed usefulness of cytology for rapid intraoperative diagnosis of intracranial tumors using frozen section. Twenty five cases of intracranial tumors (6 cases of astrocytoma, 6 cases of glioblastoma multiforme, 4 cases of meningioma, 2 cases of pituitary adenoma, 1 case of ependymoma and 6 cases of metastatic carcinoma) were observed by cytological specimen, frozen section and formalin fixed-paraffin embedded section. When only frozen section were used for histopathological diagnosis, it was difficult to diagnose in a few case of astrocytic tumors by artifact in freezing process. When only cytological specimen were used for diagnosis, histological findings, for example pseudopalisading around necrosis in glioblastoma or rosette formation in ependymoma, were not identified. However, diagnostic accuracy were improved when both cytological and frozen specimen were used if adequate material were obtained for diagnosis. In conclusion, cytological approach used in addition to frozen section was useful for rapid intraoperative diagnosis.

Estimation of dose absorbed fraction for 131I-beta rays in rat thyroid

The dose absorbed fraction of rat thyroid by internal deposit of 131I has been calculated as a function of effective diameter of thyroid. The calculations were done using two types of Monte Carlo simulations: one was by a simple energy-loss calculation in spherical volume according to the electron stopping power, and another by a more realistic simulation using Monte Carlo N-Particle Transport code system Version 4A (MCNP). These two calculations were consistent with each other within a deviation of 5%. The absorbed fractions in spherical thyroid were drastically changed up to 5 mm diameter, and then almost all energy was deposited within 10 mm diameter. For the practical application to the animal experiment, the absorbed fractions of ellipsoid-shaped thyroids were also calculated for 1-, 4- and 9-week-old rats, where the fractions were estimated to be 0.61, 0.67 and 0.68, respectively. It was also found that the absorbed fraction of the ellipsoid with various dimensions can be simulated by a calculation for spherical volume with a comparable effective diameter.

High concentration of L-arginine suppresses nitric oxide synthase activity and produces reactive oxygen species in NB9 human neuroblastoma cells

Hereditary argininemia manifests as neurological disturbance and mental retardation, features not observed in other amino acidemias. The cytotoxic effect of a high concentration of L-arginine (L-Arg) was investigated using NB9 human neuroblastoma cells (NB9), which express neuronal nitric oxide synthase (nNOS). When the concentration of L-Arg in the medium increased from 50 microM to 2 mM after incubation for 48 hr, the intracellular concentration of L-Arg increased from 68.0 +/- 1 pmol/10(6) cells to 1310.0 +/- 5 pmol/10(6) cells and that of L-citrulline (L-Cit) from undetectable levels to 47.1 +/- 0.2 pmol/10(6) cells (mean +/- SD of three independent analyses). This increase in intracellular L-Arg levels caused a decrease in NOS activity by approximately 71%. Flow cytometric analysis showed that reactive oxygen species (ROS) are produced in NB9 exposed to 2 mM L-Arg. The production of ROS was abolished by a NOS inhibitor, NG-nitro-L arginine-methylester. Production of ROS was also observed when NB9 were treated with L-Cit for 48 hr. To investigate the effect of L-Cit on the activity of NOS, a kinetic study on nNOS was conducted using cellular extracts from NB9. The apparent Km value of nNOS for L-Arg was 8.4 microM, with a Vmax value of 8.2 pmol/min/mg protein. L-Cit competitively inhibited NOS activity, as indicated by an apparent Ki value of 65 nM. These results suggest that L-Cit formed by nNOS in L-Arg-loaded neuronal cells inhibits NOS activity and nNOS in these L-Arg-loaded cells functions as a NADPH oxidase to produce ROS, which may cause neurotoxicity in argininemia.

Long-term results of porcine bioprostheses in the tricuspid position

From January 1976 to September 1994, 26 patients underwent a tricuspid valve replacement (TVR) with porcine bioprostheses (Hancock II in 19 patients, Carpentier-Edwards in 3, Hancock standard in 2, Medtronic-Intact in 1, and Liotta in 1). The mean age of these patients was 38.4 years (range, 9 to 70 years). The mean follow-up period was 6.7 years (range, 1.8 to 16.5 years). There was a complete follow-up in 100%. There were two hospital deaths and three late deaths. The actuarial survival rate at 16 years was 78.7%+/-8.6%. Five patients developed structural deterioration. Four of these 5 patients underwent re-TVR. The actuarial freedom rate from structural deterioration at 10 years was 47.1%+/-19.1%. There were no instances of thromboembolism and prosthetic valve endocarditis. Our experience indicated the major problem of the porcine bioprostheses in the tricuspid position thus to be valve durability: however, the long-term actuarial survival rate was satisfactory, including no operative morality with re-TVR due to tricuspid prosthetic structural deterioration. We therefore conclude that the choice of a porcine bioprosthesis in the tricuspid position should be considered not only for patients with isolated tricuspid valve disease, but also for the patients who have not previously received mechanical valves in the mitral or the aortic valve position.

[Operative results and long-term prognosis of type A acute aortic dissection]

Between 1983 and 1997, we operated upon 91 patients with type A acute aortic dissection. The dissection was localized in 22 patients and extensive in 69 patients. All patients underwent graft replacement and 61 (67%) patients underwent simultaneous replacement of ascending aorta and total aortic arch. The hospital mortality rate were 9% for the localized dissection and 21% for the extensive dissection. The actuarial survival rates in patients with localized dissection at 5 and at 10 years was 91% and 76%, whereas those in patients with extensive dissection at 5 and at 10 years was 68% and 62%. The freedom from dissection related death or reoperation in operative survivors with localized dissection at 5 and at 10 years was 100% and 83%, whereas those in patients with extensive dissection at 5 and at 10 years was 78% and 56%. The simultaneous replacement of ascending aorta and total aortic arch in patients with extensive dissection was effective to obliteration of the distal false channel, although this extended procedure has to be carefully adopted in high risk patients with associated complications such as acute dissection organ ischemia.

Fine localization of the Nijmegen breakage syndrome gene to 8q21: evidence for a common founder haplotype

Nijmegen breakage syndrome (NBS) is a rare autosomal recessive disorder characterized by microcephaly, a birdlike face, growth retardation, immunodeficiency, lack of secondary sex characteristics in females, and increased incidence of lymphoid cancers. NBS cells display a phenotype similar to that of cells from ataxia-telangiectasia patients, including chromosomal instability, radiation sensitivity, and aberrant cell-cycle-checkpoint control following exposure to ionizing radiation. A recent study reported genetic linkage of NBS to human chromosome 8q21, with strong linkage disequilibrium detected at marker D8S1811 in eastern European NBS families. We collected a geographically diverse group of NBS families and tested them for linkage, using an expanded panel of markers at 8q21. In this article, we report linkage of NBS to 8q21 in 6/7 of these families, with a maximum LOD score of 3.58. Significant linkage disequilibrium was detected for 8/13 markers tested in the 8q21 region, including D8S1811. In order to further localize the gene for NBS, we generated a radiation-hybrid map of markers at 8q21 and constructed haplotypes based on this map. Examination of disease haplotypes segregating in 11 NBS pedigrees revealed recombination events that place the NBS gene between D8S1757 and D8S270. A common founder haplotype was present on 15/18 disease chromosomes from 9/11 NBS families. Inferred (ancestral) recombination events involving this common haplotype suggest that NBS can be localized further, to an interval flanked by markers D8S273 and D8S88.

Positional cloning of the gene for Nijmegen breakage syndrome

Nijmegen breakage syndrome (NBS), also known as ataxia-telangiectasia (AT) variant, is an autosomal recessive disorder characterized by microcephaly, growth retardation, severe combined immunodeficiency and a high incidence of lymphoid cancers. Cells from NBS patients display chromosome instability, hypersensitivity to ionizing radiation and abnormal cell-cycle regulation after irradiation, all of which are characteristics shared with AT. Recently, the NBS locus was mapped at 8q21 by two independent approaches, complementation studies and linkage analysis. Here, we report the positional cloning of the NBS gene, NBS1, from an 800-kb candidate region. The gene comprises 50 kb and encodes a protein of 754 amino acids. The amino-terminal region of the protein shows weak homology to the yeast XRS2, MEK1, CDS1 and SPK1 proteins. The gene is expressed at high levels in the testes, suggesting that it might be involved in meiotic recombination. We detected the same 5-bp deletion in 13 individuals, and conclude that it is likely to be a founder mutation.

Congenital ectopic nail with bone deformity

This report describes two cases of congenital ectopic nail with bone deformity. Histologically, the squamous epithelium of the nail matrix lacked a definite granular layer. Resected nail tissue was connected with the periosteum of the tip of the ungual phalanx, which suggested that the contact of the ectopic nail matrix with the periosteum could impede intramembranous ossification and deform the bone shape.

Is atrial fibrillation resulting from rheumatic mitral valve disease a proper indication for the maze procedure?

BACKGROUND

There are a few patients without detectable atrial contraction despite restoration of atrial rhythm after the maze procedure for atrial fibrillation (AF) associated with mitral valve disease.

METHODS

From January 1995 to March 1997, 29 consecutive patients with AF associated with mitral valve disease underwent our modified maze procedure combined with mitral or other valve operations. The causes of mitral valve disease were rheumatic mitral stenosis (n = 22) and nonrheumatic mitral regurgitation (n = 7). The 17 patients with postoperative atrial rhythm were divided into group I with rheumatic mitral stenosis (n = 10), and group II with mitral regurgitation of nonrheumatic origins (n = 7).

RESULTS

Seventeen patients regained atrial rhythm, 2 patients had junctional rhythm, and another 10 remained in AF. Between the group of patients with restoration of atrial rhythm and that of patients remaining in AF, significant differences were found in the percentage with rheumatic disease, history of AF, and maximum f-wave voltage. The postoperative peak velocity of the atrial filling wave to peak velocity of early filling wave ratio for the left atrium measured using Doppler echocardiography was 0.25 in group I, which was significantly lower than that (0.42) in group II.

CONCLUSIONS

Reconsideration of the indications for the maze procedure for AF associated with rheumatic mitral stenosis may thus be reasonable, particularly for cases in which replacement using a prosthetic valve is necessary, but we believe that patients with nonrheumatic mitral valve disease, especially those able to undergo reconstructive operations, are the best candidates for the maze procedure.

Developmental malformations and intrauterine deaths in gamma-ray-irradiated scid mouse embryos

PURPOSE

To examine the induction by radiation of developmental malformations and intrauterine deaths in severe combined immunodeficiency (scid) mice.

MATERIALS AND METHODS

The scid embryos, as well as those of C.B-17 control mice, were irradiated with graded doses of 60Co gamma-rays on gestation day 8.

RESULTS

Intrauterine deaths in scid mice increased with radiation dose, and their frequency was substantially higher than in C.B-17 mice. The LD50 for intrauterine death in scid mice was 0.58 Gy and 1.25 Gy in C.B-17 mice. In addition, after irradiation scid mice showed several types of developmental malformations, including meningoencephalocele, spina bifida, eye defects, tail defects and oedema. Malformation incidences were higher in scid than in C.B-17 mice: 33.3% in scid mice irradiated with 0.75 Gy and 13.0% in C.B-17 mice irradiated with 1.0 Gy. However, when malformation incidences were plotted against intrauterine deaths, all the data, irrespective of the type of mouse, essentially fell along a single straight line.

CONCLUSIONS

These results suggest that some mechanism common to both scid and normal mice induces developmental malformations. This mechanism involves cell killing. Residual DNA damage, such as double-strand breaks, could be associated with radiation-induced teratogenesis.

Probability estimation of final height

13,707 longitudinal records of individuals (6,749 boys and 6,958 girls) from 6 years to 17 years were fitted by means of a smoothing cubic spline function and the factors influencing the change in height SDS during puberty were analysed. Children are divided into subgroups with 0.2 SD intervals according to height SDS at 6 years. Shorter children in subgroups at 6 years tend to increase their final height SDS by entering puberty later and making their height at onset of pubertal growth spurt (PGS) relatively taller. On the other hand taller children in subgroups at 6 years tend to decrease their final height SDS by entering puberty early and make height at PGS relatively shorter. The percentage distribution of a final height SDS against subgroups at 6 years also shows this tendency. This figure is useful in predicting the probability of final height SDS in the clinical field of growth disorders.

Comparison of biomechanical properties of the incisor periodontal ligament among different species

BACKGROUND

The aim of this study was to obtain a more precise understanding of the mechanical properties of the periodontal ligament in continuously erupting incisors by comparing the shear stress-strain relations among teeth from four closely related species.

METHODS

Four species of experimental animals (mice, hamsters, rats, and rabbits) were used. Transverse sections of the left mandibular incisors were cut from the incisal, middle, and basal regions of each incisor. The tooth was pushed out of the alveolar bone in an extrusive direction at 5 mm/min using a materials testing machine. The maximum shear stress, maximum shear strain, tangent modulus, and failure strain energy density were estimated from the resulting stress-strain curve. Polarized light microscopic observations of collagen fibers were also made.

RESULTS

All the biomechanical measures tended to decrease from the incisal toward the basal regions in all species. There were large species differences, especially in the incisal region, with the greatest maximum shear stress and failure strain energy density in hamsters. The greatest tangent modulus and the smallest maximum shear strain were observed in mice. The birefringent fiber architectures of the periodontal ligaments in the four species appeared to be similarly organized; the incisal periodontal ligament appeared to have more organized and thicker collagen fibres than did the middle and basal ligaments in the four species.

CONCLUSIONS

These results suggest that the regional differences in the biomechanical properties of the periodontal ligament depend upon the developmental stages of the periodontal collagen fibers that may be related to the general arrangement, diameters, and densities of the collagen fiber bundles and the fiber insertions into the alveolar bone and cementum. The species differences in the biomechanical properties may be due to differences in the width of the periodontal ligament and the waviness as well as the strength and stiffness of the periodontal collagen fibers.

Change in bladder contractility associated with bladder overactivity in rats with cerebral infarction

PURPOSE

To evaluate the contractile properties of overactive bladder from rats in the chronic stage of experimental cerebral infarction.

MATERIALS AND METHODS

Cystometry was performed in conscious male S-D rats after inducing occlusion of the left middle cerebral artery. Bladder muscle strips were evaluated for force development in response to field stimulation, acetylcholine and KCl. By measuring the contractile response to field stimulation after adding atropine and alpha,beta-methylene-ATP, contributions of cholinergic and purinergic transmission were determined.

RESULTS

Bladder capacity of cerebral-infarcted rats was <50% of the capacity of sham-operated rats and significantly less than that of sham-operated rats even 4 months after surgery. There was no significant difference in bladder weight between sham-operated rats and cerebral-infarcted rats. No differences in the contractile response of detrusor strips to field stimulation and acetylcholine, or in the relative contribution of cholinergic and purinergic transmission to the contractile response, were observed over time or between strips from sham-operated rats and cerebral-infarcted rats. KCl induced significantly less contraction in strips from 4 month infarcted rats than in strips from 4 month sham-operated rats, 2 week infarcted rats and 2 month infarcted rats.

CONCLUSIONS

This animal model will be useful for chronic studies on the mechanism of detrusor hyperactivity (DH).

Effects of MK-801 on bladder overactivity in rats with cerebral infarction

PURPOSE

Our objective was to evaluate the underlying mechanisms of neurogenic voiding dysfunction following cerebral infarction.

MATERIALS AND METHODS

The left middle cerebral artery (MCA) was occluded using 4-0 monofilament nylon thread in male S-D rats. Cystometric examination was performed in unanesthetized and urethane-anesthetized rats through a catheter chronically implanted in the dome of the bladder.

RESULTS

Bladder capacity of unanesthetized or urethane anesthetized rats was significantly reduced just after occlusion of the left MCA; 2 weeks after the occlusion, the capacity was less than half that in sham-operated rats. Intravenous administration of N-methyl-d-aspartate (NMDA) receptor antagonist MK-801 to the unanesthetized sham-operated rats led to a marked dose-dependent decrease in bladder capacity. Its administration to unanesthetized rats with cerebral infarction resulted in a slight decrease in bladder capacity. In the urethane-anesthetized state, the bladder capacity of the rats with cerebral infarction was significantly increased by MK-801, 0.1 mg./kg., without inhibiting the contraction pressure or increasing the amount of residual urine. A high dose (1 mg./kg.) of MK-801 was required to increase the bladder capacity of sham-operated rats. This led to an inhibition of contraction pressure and an increase in residual urine.

CONCLUSION

Results in urethane anesthetized rats indicate that NMDA glutamatergic transmission is important in the overactivity of the bladder following a cerebral infarction. This model is useful in studying the neurogenic voiding dysfunction observed in patients with cerebrovascular disease.

[Relationship between cardiac output and PETco2 as well as Paco2 during high-dose fentanyl anesthesia]

We investigated the relationship between cardiac output and PETCO2 as well as blood PCO2 in 10 patients undergoing cardiac surgery of long duration under high-dose fentanyl anesthesia. After anesthetic induction, the minute ventilation was kept constant at 10 ml.kg-1 x 10 cycles.min-1 and a pulmonary artery catheter was inserted. PETCO2, PaCO2 and cardiac index (CI) were measured simultaneously. PaCO2 was corrected for body temperature, and alveolar dead space-to-tidal volume ratio was calculated as VD/VTalv = (PaCO2-PETCO2)/PaCO2. After body, temperature became stabilized, the measurements were started and repeated every 10 to 20 minutes during the prebypass period. One hundred and eight sets of data were taken from 10 patients. PETCO2 correlated positively with CI. Similarly, PaCO2 correlated positively with CI, but VD/VTalv, did not correlate with CI. PETCO2 correlated closely and positively with PaCO2, but it correlated negatively and only marginally with VD/VTalv. When examined in individual patients, PaCO2 correlated positively with PETCO2 in all patients, while VD/VTalv correlated negatively with PETCO2 only in 3 patients. By multiple regression analysis, VD/VTalv change accounted for only 22.3 +/- 15.0% of PETCO2 change, while PACO2 or PaCO2 change accounted for 77.6 +/- 15.0% of PETCO2 change. Decreased CI was associated with decreased CO2 delivery from the tissue to the lung (DCO2) and PaCO2 decreased with decreasing DCO2. Decreased CI was also associated with decreased oxygen uptake (VO2), and PaCO2 decreased with decreasing VO2. A decrease in CI resulted in an increase in VA/Q, and PaCO2 decreased when VA/Q increased. PETCO2 decreased when cardiac output decreased. A decrease in PACO2 explained the decrease in PETCO2 better than an increase in VD/VT did. Decreased cardiac output might cause hypocapnia through decreased CO2 delivery to the lung, decreased CO2 production and/or increased ventilation-to-perfusion ratio.

Radiation induction of p53 in cells from Nijmegen breakage syndrome is defective but not similar to ataxia-telangiectasia

p53-mediated signal transduction after exposure to ionizing radiation was examined in cells from patients with Nijmegen breakage syndrome (NBS), an autosomal recessive disease characterized by microcephaly, immunodeficiency, predisposition to malignancy, and a high sensitivity to ionizing radiation. NBS cells accumulated p53 protein in a dose-dependent fashion, with a peak level 2 hrs after irradiation with 5 Gy. However, the maximal level of p53 protein in NBS cells was constantly lower than in normal cells. Moreover, this attenuation of p53 induction was confirmed by decreased levels of p21WAF1 protein, which is transcriptionally regulated by p53 protein. This defective induction of p53 protein in NBS is similar to that in ataxia-telangiectasia (AT), although the induced levels of p53 protein in NBS appeared to be the intermediate between normal cells and AT cells. This moderate p53 induction in NBS cells is consistent with the relatively mild radiation sensitivity and the abnormal cell cycle regulation post-irradiation, as present in NBS. Furthermore, all NBS cell lines used here exhibited time courses of p53 induction similar to normal cells, which is in contrast with p53 induction in AT cells, where the maximum induction shows a delay of approximately 2 hrs compared with normal cells. These evidences suggest a different function of each gene product in an upstream p53 response to radiation-induced DNA damage.

Influence of pulmonic position on durability of bioprosthetic heart valves

BACKGROUND

The insertion of bioprosthetic valves into the pulmonic position is not performed commonly because of uncertainty concerning the necessity and durability of such valves.

METHODS

We reviewed the long-term outcome of 10 patients who underwent pulmonary valve replacement with bioprostheses between March 1985 and March 1997. A Carpentier-Edwards supraannular bioprosthesis was used in 7 patients, a Hancock II bioprosthesis was used in 2 patients, and a Carpentier-Edwards pericardial bioprosthesis was used in 1 patient. The mean patient age at the time of pulmonary valve replacement was 38.9 +/- 16.3 years (range, 15 to 63 years). The diagnoses were pulmonary valvular regurgitation after corrective surgery for tetralogy of Fallot in 7 patients, right ventricular outflow tract stenosis and absent right pulmonary artery combined with a double-outlet right ventricle in 1 patient, pulmonary valvular regurgitation with pulmonary artery dilatation in 1 patient, and aortic valve stenosis treated with our modification of the Ross procedure using a pulmonary bioprosthesis in 1 patient. Survivors were followed up for a mean of 5 years and 5 months.

RESULTS

One patient underwent reoperation because of infective endocarditis of the bioprosthesis. No bioprosthetic valve dysfunction has been observed on Doppler echocardiography during a maximum follow-up period of 12.2 years, except in the patient who underwent replacement at 15 years of age.

CONCLUSIONS

Bioprostheses in the pulmonic position are durable in adult patients because they face a minimal hemodynamic load, but they may undergo early leaflet degeneration in younger patients.

Dose-response effects of adrenergic drugs on axial movements of the rat mandibular incisor and on arterial blood pressure

Axial tooth movements and arterial blood pressure were measured following the intravenous injection of 0, 0.01, 0.1, 1, or 10 micrograms/kg of adrenaline, noradrenaline or isoprenaline. Adrenaline caused a dose-dependent, rapid, extrusive tooth movement with a nearly simultaneous increase in blood pressure, followed by a marked intrusive tooth movement and a decrease in blood pressure. Noradrenaline caused a dose-dependent, rapid, extrusive tooth movement and an increase in blood pressure, but a subsequent intrusive tooth movement and decrease in blood pressure were not so marked. Isoprenaline caused a marked intrusive tooth movement and a decrease in blood pressure, without an extrusive tooth movement and increase in blood pressure. The time required to reach the maximum intrusive tooth movement was delayed after that to reach the maximum decrease in blood pressure. The recovery time of the intrusive tooth movement was much more delayed than that of blood pressure. These results suggest that the extrusive movement of the rat incisor was primarily related to the rise of arterial blood pressure due to stimulation of vascular alpha-receptors. It is also suggested that stimulation of beta-receptors would probably cause vasodilatation of arteries that would make the pressure in the small vessels in the microcirculation of the socket fall, so reducing the volume of blood and interstitial fluid in the socket followed by a marked and continuing intrusive tooth movement.

[Redo operation for recurrent pulmonary artery aneurysm associated with pulmonary stenosis and regurgitation]

A 63-year-old woman who underwent surgical correction of a recurrent pulmonary artery aneurysm associated with pulmonary stenosis and regurgitation is reported. On April 1986, she underwent commissurotomy of pulmonary valve, reconstruction of right ventricle out flow tract using a Polystan monocusp patch and pulmonary aneurysmorrhaphy for pulmonary artery aneurysm. Pathological examination of the resected pulmonary arterial wall revealed mucoid degeneration of media and fragmentation of elastic fiber. Nine years after the operation, recurrence of pulmonary artery aneurysm, pulmonary stenosis and regurgitation were recognized. On September 1995, she underwent redo operation with graft replacement of pulmonary artery and pulmonary valve replacement using woven Dacron prosthesis containing a Carpentier-Edwards bioprosthetic valve. We should choose as an initial procedure with graft replacement for pulmonary artery aneurysm with fragility of the pulmonary arterial wall. She is now doing very well at one year and 5 months after the redo operation.

A multicentre randomized controlled trial of recombinant interferon-alpha-2a in the treatment of patients with chronic hepatitis C

Sixty-one chronic hepatitis C patients were randomly assigned to receive either 6 x 10(6) or 9 x 10(6) U of recombinant interferon-alpha-2a (IFN alpha-2a) six days a week for the first two weeks of treatment, followed in both cases by 6 x 10(6) U three days a week for the next 22 weeks. In the low dose group, 11 patients showed a complete response maintained for at least six months, 12 responded but then relapsed and nine did not respond; the corresponding figures in the high dose group were 10, 15 and five patients, respectively. The differences between groups are not statistically significant. Thus, this study provides no evidence of therapeutic benefit from increasing the initial dose of IFN alpha-2a. In both treatment groups, complete responders had significantly lower pretreatment viral titres than nonresponders and were significantly more likely to be infected by type 2a versus type 1b virus.

[Effects of cardiac output on PETCO2 and PaCO2 during combined inhalational-epidural anesthesia]

We investigated the effects of cardiac output on PETCO2 in anesthetized patients. We studied 8 adult patients undergoing long-lasting lower abdominal surgery. Anesthesia was maintained with epidural combined with inhalational anesthesia. The minute ventilation volume was kept constant at 10 ml.kg-1 x 10 cycles.min-1. PETCO2, PaCO2, and cardiac index, (CI) by thermodilution method were measured simultaneously. PaCO2 was corrected for body temperature for comparison with PETCO2. Approximate value of alveolar dead space to tidal volume ratio was calculated as VD/ VTalv = (PaCO2-PETCO2)/PaCO2. The measurements were repeated every 10 to 20 minutes under the steady body temperature. One hundred and six sets of data were obtained from these patients. PETCO2 as well as PaCO2 correlated positively with CI, while VD/VTalv did not correlate with CI. PETCO2 correlated positively with PaCO2, while it did not correlate with VD/VTa1v. When examined in individual patients, PETCO2 correlated positively with CI in 7 patients. PaCO2 correlated positively with CI in 6 patients, while VD/VTa1v correlated negatively with CI only in 2 patients, in whom CI showed a large fluctuation. PaCO2 correlated positively with PETCO2 in 8 patient, while VD/VTa1v correlated negatively with PETCO2 only in 1 patient. By multiple regression analysis, VD/VTa1v change accounted for only 20.0 +/- 15.3% of PETCO2 change, while PACO2 or PaCO2 change accounted for 79.3 +/- 16.7%. Decreased CI was associated with a decrease in oxygen uptake (VO2), and PaCO2 correlated positively with VO2. Decreased CI was also associated with an increase in VA/Q, and PaCO2 correlated negatively with VA/Q. Thus, PETCO2 decreased with decreasing cardiac output. A decrease in PACO2 explained the decrease in PETCO2 better than an increase in VD/VT did. Decreased cardiac output caused hypocapnia through decreased CO2 production and/or increased ventilation to perfusion ratio i.e. relative hyperventilation.