Ischemically mediated sustained monomorphic ventricular tachycardia. Resolution with anti-ischemic therapy

We describe a patient with ischemically mediated sustained monomorphic ventricular tachycardia occurring at rest and resistant to treatment with intravenously administered procainamide. Percutaneous transluminal coronary angioplasty was initially successful, but rest angina and ventricular tachycardia, resistant to procainamide therapy, recurred 2 weeks later and responded to aggressive anti-ischemic medical therapy. We suggest that anti-ischemic medication may be of benefit in patients with malignant ventricular arrhythmias precipitated by spontaneous myocardial ischemia.

Expression of cellular oncogenes in human gastric carcinoma: c-myc, c-erb B2, and c-Ha-ras

Expression of oncogenes in gastric cancer tissue was evaluated with immunohistochemical staining methods using monoclonal antibodies to products of the oncogenes. Rates of expression in gastric cancer tissue were 50% for c-myc, 72% for c-erb B2, and 56% for c-Ha-ras oncogenes. Expression of these oncogenes in gastric cancer was not correlated with the histologic differentiation. The c-Ha-ras oncogene was positive in 19 of 26 cases with lymph node and/or distant metastasis: the positive rate was significantly higher than in cases without metastasis. Results suggest that c-Ha-ras oncogene is related to the prognosis of gastric cancer. The rate of expression of c-myc and c-Ha-ras oncogenes in gastric cancer tissues was higher in the DNA aneuploid group than in the DNA diploid group. Expression of c-myc and c-Ha-ras oncogenes correlated with other prognostic factors such as DNA ploidy pattern and metastasis. These oncogenes can be used to evaluate prognosis of gastric cancer patients.

Spinal congenital dermal sinus--experience of 5 cases over a period of 10 years

Spinal congenital dermal sinus (CDS) is a rare entity which supposedly results from the failure of the neuroectoderm to separate from the cutaneous ectoderm during the process of neurulation. The lesions are most frequent at the lumbosacral followed by the occipital region. CDS of the thoracic region is very rare. The patients with spinal CDS present with meningitis and/or mass effect from the associated inclusion tumor. They are usually dermoid or epidermoid cysts. Teratoma is rarely associated. The authors experienced 5 cases of spinal CDS over a 10 year period. Of the 5 cases, 2 were at thoracic and 3 were at lumbosacral levels. Dermoid cyst, epidermoid cyst and teratoma were associated in one case each. Two cases presented with neurological deficit and meningitis while an additional case presented with neurological deficit and a history of probable meningitis. Pain was present in 2 cases. Magnetic resonance imaging played an important role in the diagnosis of the lesion and planning of surgery. All the cases showed a good response to surgery even though one patient had persistent neurological deficit.

Cerebral aspergillosis in immunologically competent patients

Aspergillosis of the central nervous system is a rare disease, especially if the patient's immune system is not compromised. The authors report three cases of cerebral aspergillosis in the immunocompetent state: a rhinocerebral form in a diabetic patient, a direct extension from chronic Aspergillus otitis media, and a postoperative Aspergillus brain abscess after brain tumor surgery. In spite of the poor prognosis of cerebral aspergillosis, two of the patients survived. The pathogenesis, predisposing factors, radiologic findings including magnetic resonance image, and the outcome are presented. The pertinent literature of cerebral aspergillosis is also reviewed.

A physiological and system analysis hybrid pharmacokinetic model to characterize carbon tetrachloride blood concentrations following administration in different oral vehicles

Oral absorption of chemicals can be influenced significantly by the administration vehicle or diluent. It has been observed that the oral absorption of carbon tetrachloride (CCl4) and other volatile organic chemicals is markedly affected by the dosing vehicle, with administration in oils producing erratic blood concentration-time profiles with multiple peaks. Analysis of this type of data by a compartmental modeling approach can be difficult, and requires numerous assumptions about the absorption processes. Alternatively, a system analysis method with few assumptions may provide a more accurate description of the observed data. In the current investigations, a nonlinear system analysis approach was applied to blood CCl4 concentration-time data obtained following iv and oral administration. The oral regimens consisted of 25 mg CCl4/kg body wt given as an aqueous emulsion, in water, as pure chemicals, and in corn oil. The system analysis procedure, based upon a disposition decomposition method, provided an absorption input rate function, F, for each regimen. A physiological pharmacokinetic model, based primarily on parameters available in the literature, and the F input functions, formed a hybrid model that adequately described the observed blood CCl4 concentration-time data. The same physiological pharmacokinetic model, employing conventional first-order absorption input schemes, did not predict the data as well. Overall, the system analysis approach allowed the oral absorption of CCl4 to be characterized accurately, regardless of the vehicle. Though system analysis is based on general mathematical properties of a system's behavior rather than on its causal mechanisms, this work demonstrates that it can be a useful adjunct to physiological pharmacokinetic models.

CT diagnosis of superior vena cava syndrome: importance of collateral vessels

OBJECTIVE

The purpose of this study was to evaluate the importance of collateral vessels in the CT diagnosis of superior vena cava syndrome.

MATERIALS AND METHODS

Forty-seven patients with CT evidence of obstruction or compression of the superior vena cava or its major tributaries were included in this study. Contrast-enhanced CT scans had been obtained with a combined bolus and drip-infusion technique. We evaluated the CT scans, with particular attention to the presence of collateral vessels (and if present, their location), without knowing the patients' clinical histories. On reviewing the patients' charts, we found 23 patients with signs or symptoms of superior vena cava syndrome. We then correlated the presence of collateral vessels with the presence of signs and symptoms of superior vena cava syndrome. To verify the frequency of visible collateral vessels in healthy subjects, we also evaluated CT scans of 50 control subjects who did not have mediastinal disease or signs and symptoms of superior vena cava syndrome.

RESULTS

Collateral vessels were seen on CT scans in 24 patients. Among the 23 patients who had signs and symptoms of superior vena cava syndrome, 22 patients had CT scans that showed collateral vessels. Two cases were false-positive and one was false-negative. The presence of collateral vessels, regardless of the number and location of the vessels shown on CT scans, was highly accurate as a predictor of superior vena cava syndrome, with a sensitivity of 96% and a specificity of 92%. Collateral vessels were seen in three (6%) of the 50 control subjects.

CONCLUSION

We conclude that the presence of collateral vessels is a highly sensitive and specific CT sign of superior vena cava syndrome.

A phase III randomized study of 5-fluorouracil and cisplatin versus 5-fluorouracil, doxorubicin, and mitomycin C versus 5-fluorouracil alone in the treatment of advanced gastric cancer

BACKGROUND

With the introduction of cisplatin-containing regimens in the treatment of advanced gastric cancer, promising clinical results have been reported. A 61.5% response rate was observed with a combination of 5-fluorouracil (5-FU) infusion and bolus cisplatin; however, the superiority of cisplatin-containing regimens to other regimens has not been clearly verified in any randomized controlled studies. A prospective, randomized study of 5-FU and cisplatin (FP) versus 5-FU, doxorubicin, and mitomycin C (FAM) versus 5-FU alone (FU) in previously untreated patients with advanced gastric cancer is reported.

METHODS

A total of 324 patients were entered into the trial and 295 patients (103 for FP, 98 for FAM, 94 for FU) were evaluable. The patients were randomized to receive FP, FAM, or FU after stratifying by the following factors: performance status, presence of measurable disease, and resection of the primary tumor.

RESULTS

The overall response rate for patients with measurable disease in the FP arm was significantly higher than in the FAM and FU arms (51% for FP; 25% for FAM; 26% for FU). The durations of response for each arm, however, were not significantly different. Even though the median time to progression for the FP arm (21.8 weeks) was longer than that for the FAM arm (12 weeks; P < 0.05) and for the FU arm (9.1 weeks; P < 0.005), there was no statistical difference in overall survival among the three arms. Toxicity for all three regimens was moderate and consisted primarily of myelosuppression, nausea, vomiting, and alopecia.

CONCLUSIONS

Although the FP regimen showed a significantly higher response rate and a longer time to progression than the FAM or FU regimens, a survival benefit was not observed.

A phase III randomized study of 5-fluorouracil and cisplatin versus 5-fluorouracil, doxorubicin, and mitomycin C versus 5-fluorouracil alone in the treatment of advanced gastric cancer

BACKGROUND

With the introduction of cisplatin-containing regimens in the treatment of advanced gastric cancer, promising clinical results have been reported. A 61.5% response rate was observed with a combination of 5-fluorouracil (5-FU) infusion and bolus cisplatin; however, the superiority of cisplatin-containing regimens to other regimens has not been clearly verified in any randomized controlled studies. A prospective, randomized study of 5-FU and cisplatin (FP) versus 5-FU, doxorubicin, and mitomycin C (FAM) versus 5-FU alone (FU) in previously untreated patients with advanced gastric cancer is reported.

METHODS

A total of 324 patients were entered into the trial and 295 patients (103 for FP, 98 for FAM, 94 for FU) were evaluable. The patients were randomized to receive FP, FAM, or FU after stratifying by the following factors: performance status, presence of measurable disease, and resection of the primary tumor.

RESULTS

The overall response rate for patients with measurable disease in the FP arm was significantly higher than in the FAM and FU arms (51% for FP; 25% for FAM; 26% for FU). The durations of response for each arm, however, were not significantly different. Even though the median time to progression for the FP arm (21.8 weeks) was longer than that for the FAM arm (12 weeks; P < 0.05) and for the FU arm (9.1 weeks; P < 0.005), there was no statistical difference in overall survival among the three arms. Toxicity for all three regimens was moderate and consisted primarily of myelosuppression, nausea, vomiting, and alopecia.

CONCLUSIONS

Although the FP regimen showed a significantly higher response rate and a longer time to progression than the FAM or FU regimens, a survival benefit was not observed.

Evaluation of reconstruction algorithms in SPECT neuroimaging: II. Computation of deterministic and statistical error components

For the reconstruction of a series of computer simulations of statistically-independent noisy realizations of projection data, the total error of the ith reconstructed voxel in the rth realization, Er,i, is composed of the statistical error, Sr,i, and the (deterministic) inaccuracy in the presence of noise, Di+. Di+ is composed of the (deterministic) inaccuracy in the absence of noise, Di-, and the (deterministic) additional inaccuracy in the presence of noise, Di delta. E(Er,i), the theoretical expected value of Er,i, is given by E(Er,i) = E(Di+) + E(Sr,i). Similarly, E(Di+) = E(Di-) + E(Di delta). The corresponding theoretical variances are given by sigma 2(Er,i) = sigma 2(Di+)+2C(Di+, Sr,i)+ sigma 2(Sr,i) and sigma 2(Di+) = sigma 2(Di-)+2C(Di-, Di delta)+ sigma 2(Di delta), where C(.,.) is the covariance. We have utilized these relationships to evaluate three reconstruction algorithms: standard filtered back projection (FBP), an iterative reconstruction algorithm (IRA), and a version of the IRA which incorporates a linear transformation (TIRA). For simulated brain images in which the projection data (500,000 events detected) were degraded as the result of convolution of the true radioactivity distribution with a realistic distance-dependent detector response function, for FBP the major contribution to both E(Er,i) and sigma 2(Er,i) was Di-. For the IRA and TIRA, the major contributions to E(Er,i) were Di- and Di delta, and the major contribution to sigma 2(Er,i) was Sr,i, although in some cases Di delta was also a contributing factor. Furthermore, the errors due to sigma 2(Er,i) (that is, [sigma 2(Er,i)]0.5) were more severe than those due to E(Er,i). We conclude that, in contrast to FBP, the effects of statistical noise are an important limiting factor for the IRA and TIRA, and that the future development of tomographic devices with higher sensitivity would expand the quantitative potential of the IRA and TIRA.

Antidromic sensory nerve conduction studies of medial and lateral plantar nerves in normals

A reliable sensory nerve conduction study for the most distal lower extremities is needed in routine clinical electromyography. This paper reports a study of 150 medial and lateral plantar nerves in the foot in normals. An antidromic technique was used with stimulation at the ankle and recording from the small and large toes. Recordable responses were obtained in 149 instances. Conduction velocity in the medial branch distal to the tarsal tunnel was 40.5 +/- 4.0 m/sec and significantly slower than conduction in the lateral branch by 4.3 m/sec. The amplitude of the evoked response from the big toe was 3.46 +/- 2.2 microV and significantly larger than that in the small toe by 1.34 microV. Evoked response amplitude in the medial branch was greater in younger subjects.

Evaluation of reconstruction algorithms in SPECT neuroimaging: I. Comparison of statistical noise in SPECT neuroimages with 'naive' and 'realistic' predictions

In the presence of statistical noise, an iterative reconstruction algorithm (IRA) for the quantitative reconstruction of single-photon-emission computed tomographic (SPECT) brain images overcomes major limitations of applying the standard filtered back projection (FBP) reconstruction algorithm to projection data which have been degraded by convolution of the true radioactivity distribution with a finite-resolution distance-dependent detector response: (a) the non-uniformity within the grey (or white) matter voxels which results even though the true model is uniform within these voxels; (b) a significantly lower ratio of grey/white matter voxel values than in the true model; and (c) an inability to detect an altered radioactivity value within the grey (or white) matter voxels. It is normally expected that an algorithm which improves spatial resolution and quantitative accuracy might also increase the magnitude of the statistical noise in the reconstructed image. However, the noise properties in the IRA images are very similar to those in the FBP images. In fact, the noise magnitude in both the FBP and IRA images is only slightly greater than that computed by the 'naive prediction', which presumably is a lower limit to the amount of statistical noise in a reconstructed image. Thus, the IRA should provide the potential for quantitative SPECT imaging of normal physiological responses or diseases involving both the brain grey and white matter.

A phase III randomized study of 5-fluorouracil and cisplatin versus 5-fluorouracil, doxorubicin, and mitomycin C versus 5-fluorouracil alone in the treatment of advanced gastric cancer

BACKGROUND

With the introduction of cisplatin-containing regimens in the treatment of advanced gastric cancer, promising clinical results have been reported. A 61.5% response rate was observed with a combination of 5-fluorouracil (5-FU) infusion and bolus cisplatin; however, the superiority of cisplatin-containing regimens to other regimens has not been clearly verified in any randomized controlled studies. A prospective, randomized study of 5-FU and cisplatin (FP) versus 5-FU, doxorubicin, and mitomycin C (FAM) versus 5-FU alone (FU) in previously untreated patients with advanced gastric cancer is reported.

METHODS

A total of 324 patients were entered into the trial and 295 patients (103 for FP, 98 for FAM, 94 for FU) were evaluable. The patients were randomized to receive FP, FAM, or FU after stratifying by the following factors: performance status, presence of measurable disease, and resection of the primary tumor.

RESULTS

The overall response rate for patients with measurable disease in the FP arm was significantly higher than in the FAM and FU arms (51% for FP; 25% for FAM; 26% for FU). The durations of response for each arm, however, were not significantly different. Even though the median time to progression for the FP arm (21.8 weeks) was longer than that for the FAM arm (12 weeks; P < 0.05) and for the FU arm (9.1 weeks; P < 0.005), there was no statistical difference in overall survival among the three arms. Toxicity for all three regimens was moderate and consisted primarily of myelosuppression, nausea, vomiting, and alopecia.

CONCLUSIONS

Although the FP regimen showed a significantly higher response rate and a longer time to progression than the FAM or FU regimens, a survival benefit was not observed.

Arterial thrombosis associated with nephrotic syndrome--a case report and review (adult cases in the English literature)

The thromboembolic complications of nephrotic syndrome are reasonably common, including spontaneous peripheral venous and/or arterial, pulmonary arterial, and renal venous occlusions. However, in comparison to the relatively high incidence of the venous thromboembolic complications with hypercoagulable status, arterial thromboses have been reported much less and it was only 20 cases in the English literature so far. Furthermore, the most cases were pediatric patients rather than adults. Therefore, this report describes an adult nephrotic cases complicated by superior mesenteric artery thrombosis leading to death via catastrophic hospital course. Also, we reviewed the literature in English regarding cases of arterial thromboses in adult nephrotic patients with special interest to locations of thrombosis, underlying histopathologic types of glomerulopathy, and use of steroids or diuretics before its development.

A comparison of the passage of regenerating axons through old degenerated nerve autografts and fresh nerve autografts in rats

We have compared the passage of regenerating axons through old degenerated nerve autografts and fresh nerve autografts in two groups of Sprague Dawley rats. In one group the right sciatic nerve was divided and repaired with the graft taken from the distal segment of the left sciatic nerve, which had been severed 15 weeks before. In the other group the right sciatic nerve was repaired with the graft taken from the intact left sciatic nerve. Eight weeks later the myelinated axons were counted at three different locations in the grafted right sciatic nerve in both groups. The old degenerated nerve autografts were less effective in allowing the passage of regenerating axons than the fresh nerve autografts, but the difference was not great. This provides justification for the use of old degenerated nerve as an additional graft where a large number of autogenous nerve grafts are required, such as in the operative treatment of injuries to the brachial plexus.

Prediction of common folding structures of homologous RNAs

We have developed an algorithm and a computer program for simultaneously folding homologous RNA sequences. Given an alignment of M homologous sequences of length N, the program performs phylogenetic comparative analysis and predicts a common secondary structure conserved in the sequences. When the structure is not uniquely determined, it infers multiple structures which appear most plausible. This method is superior to energy minimization methods in the sense that it is not sensitive to point mutation of a sequence. It is also superior to usual phylogenetic comparative methods in that it does not require manual scrutiny for covariation or secondary structures. The most plausible 1-5 structures are produced in O(MN2 + N3) time and O(N2) space, which are the same requirements as those of widely used dynamic programs based on energy minimization for folding a single sequence. This is the first algorithm probably practical both in terms of time and space for finding secondary structures of homologous RNA sequences. The algorithm has been implemented in C on a Sun SparcStation, and has been verified by testing on tRNAs, 5S rRNAs, 16S rRNAs, TAR RNAs of human immunodeficiency virus type 1 (HIV-1), and RRE RNAs of HIV-1. We have also applied the program to cis-acting packaging sequences of HIV-1, for which no generally accepted structures yet exist, and propose potentially stable structures. Simulation of the program with random sequences with the same base composition and the same degree of similarity as the above sequences shows that structures common to homologous sequences are very unlikely to occur by chance in random sequences.

The mouse Dlx-2 (Tes-1) gene is expressed in spatially restricted domains of the forebrain, face and limbs in midgestation mouse embryos

The pattern of RNA expression of the murine Dlx-2 (Tes-1) homeobox gene is described in embryos ranging in age from E8.5 through E11.5. Dlx-2 is a vertebrate homologue of the Drosophila Distal-less (Dll) gene. Dll expression in the Drosophila embryo is principally limited to the primordia of the brain, head and limbs. Dlx-2 is also expressed principally in the primordia of the forebrain, head and limbs. Within these regions it is expressed in spatially restricted domains. These include two discontinuous regions of the forebrain (basal telencephalon and ventral diencephalon), the branchial arches, facial ectoderm, cranial ganglia and limb ectoderm. Several mouse and human disorders have phenotypes which potentially are the result of mutations in the Dlx genes.

Current transition of the physician's professionalism and doctor-patient relationship

In recent years, the physician's professionalism seemed to be facing or experiencing a phase of change. To investigate this phenomenon, social perception and attitude toward physicians were surveyed and analyzed. The subjects consisted of three types of sample group, namely, the general public, physicians, and medical students. Data were collected through interviews, mailing, and self-administered questionnaire surveys to each sample, respectively. The results of analysis showed us that social evaluation of physicians in Korean society exhibited ambivalent perceptions toward physicians. The physician's occupational status was generally evaluated by the three samples as being in a higher stratum in the social structure. But there were great gaps between their perceptions of the change in the physician's occupational status. While the general public perceived that the physician's status might improve in the future, physicians and medical students predicted an absolute declination of the status. Although the general public sympathized with the physician's characteristics as a professional group, an apparent tendency to assume the attitude of a fairly equal relationship toward physicians has increased. The transitional change in the physician's professionalism could be observed through the ubiquity in the perception of the patient's rights in doctor-patient relationships. Such phenomena are believed to have caused physicians to think that not only has their status declined in recent years but also that this declination of social status would continue in the future.

Impaired homeostatic mechanism of potassium handling after acute oral potassium load in diabetes mellitus

Chronic stable diabetic patients (n = 6) were compared with healthy control subjects (n = 5) after acute oral intake of 50 mEq of potassium chloride (KCl) to investigate for possible derangements of homeostatic responses for acute term (3 hrs) to acute potassium load. Plasma renin activity (PRA), plasma aldosterone (PA), and transtubular potassium concentration gradient (TTKG) known as a useful semiquantative index of distal nephron potassium secretion were measured. All the baseline parameters were comparable between diabetic and non-diabetic subjects except for significantly reduced creatinine clearance in diabetics (mean +/- SEM, 105 +/- 4 vs. 85 +/- 5 ml/min, p < 0.05). Following acute oral KCl load, the peak increases of serum potassium changes from basal levels were noted at 2 hours in both groups, but were higher in diabetic subjects (mean +/- SEM, 0.42 +/- 0.06 vs. 0.62 +/- 0.09 mEq/L). Also, 4 out of 6 diabetic subjects but none of the control subjects at 2 hours after oral KCl load became hyperkalemic ( > 5.0 mEq/L). PRA did not show any significant changes, whereas PA was increased simultaneously with increments in serum potassium in both groups, with blunted increases in the diabetics. However, TTKG was increased prominently in control subjects (8.18 from 4.98), but only slightly in diabetic subjects (4.55 from 4.18), with statistical difference between the two groups (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Surgical techniques and innovations in living related liver transplantation

The authors successfully performed a series of 33 living related liver transplantations (LRLT) on children (15 males and 18 females, ranging from 7 months to 15 years of age) from June 1990 to May 1992, with the informed consent of their parents and the approval of the Ethics Committee of Kyoto University. Before operation, six of the children required intensive care, another 14 were hospitalized, and 13 were homebound. Donors (12 paternal and 21 maternal) were selected solely from the parents of the recipients on the basis of ABO blood group and graft/recipient size matching determined by computed tomography scanning. Procurement of graft was performed using ultrasonic aspirator and bipolar electrocautery without blood vessel clamping and without graft manipulation. All donors subsequently had normal liver function and returned to normal life. The left lateral segment (16 cases), left lobe (16 cases), or right lobe (one case) were used as grafts. The partial liver graft was transplanted into the recipient who underwent total hepatectomy with preservation of the inferior vena cava using a vascular side clamp. Twenty-seven of 33 recipients are alive and well with the original graft and have normal liver function. The patient survival rate was 89% (24/27) in elective cases and 50% (3/6) in emergent cases. The other six recipients had functioning grafts but died of extrahepatic complications. Complications of the graft were minimal in all cases. Hepatic vein stenosis, which occurred three times in two cases, was successfully treated by balloon dilatation. In cases with sclerotic portal vein, the authors anastomosed the portal vein of the graft to the confluence of the splenic vein and the superior mesenteric vein without a vascular graft, after experiencing a case of vascular graft thrombosis. After hepatic artery thrombosis occurred in one of the initial seven recipients whose arterial anastomosis was done with surgical loupe, microsurgery was introduced for hepatic artery reconstruction. There has been no occurrence of thrombosis since then. The current results with LRLT suggested that the meticulous management of surgical factors at each stage of the LRLT procedure is crucial for successful outcome. Living related liver transplantation is a promising option for resolving the graft shortage in pediatric liver transplantation and may be regarded as an independent modality to supplement cadaver donation.

Estimation of relative regional neuroreceptor concentration by PET or SPECT: Theoretical comparisons of using a single late image or a late plus early image

The potential for using a single (SPECT) single-photon-emission computed tomography or (PET) positron emission tomography image to estimate quantitatively the relative regional neuroreceptor concentration depends on acquiring the image at a time when changes in the regional radioactivity localization are much more sensitive to changes in receptor concentration than to changes in delivery. Using the binding of [(11)C]carfentanil to the opiate receptor as a model, the authors have applied a computer simulation approach to determine the joint and marginal probability distributions for the ipsilateral/contralateral ratio of receptor concentrations and delivery. They have found that the probability distributions depend on the sensitivities for both delivery and receptor. Incorporation of data at an early time point results in a significant sharpening of the probability distributions. There is an insignificant effect of subtraction of the radioactivity localization in a control region.

Retinoids for the future: investigational approaches for the identification of new compounds

One desired goal for future retinoid development is the dissociation of therapeutic benefit from teratogenic risk. It is not known if this result can be achieved, but increasing our understanding of the molecular mechanisms of retinoid action offers rational approaches to the attainment of this goal. The basis for these new approaches is the recent discovery of nuclear receptors for all-trans-retinoic acid and for the 9-cis form of retinoic acid. These receptors, like the steroid hormone receptors, are ligand-dependent transcription factors. Retinoids act by binding to these receptors and modulating specific gene pathways that ultimately control cell differentiation and development. Retinoic acid is required for normal embryonic development, and retinoic acid concentrations are regulated in the developing embryo. The malformations associated with in utero exposure to retinoids might be the result of inappropriate activation of specific receptors and inappropriate modulation of specific gene pathways. At least three nuclear receptors for all-trans-retinoic acid and three nuclear receptors for the 9-cis form of retinoic acid are known to exist, with the two receptor subfamilies interacting to form heterodimers. This multiplicity of receptors and receptor interactions suggests that differences may exist among receptors in the biologic effects they mediate. Although some retinoid ligands are not specific, others are highly selective for one particular receptor. Contrasting the effects of ligands with different specificities should increase understanding of the biologic responses associated with specific receptors and efforts to dissociate therapeutic activity from undesired effects.

Compartmental analysis of RBC circulation through the rabbit kidney

This experiment involved 12 rabbits of both sexes, weighing 2.1 kg. After anesthesia, the kidneys were exposed, isolated and cannulated in the renal artery, ureter and sometimes in the vein as well. The kidney were perfused through the renal artery with Krebs-Henseleit solution, which were then filtered to be free of particles, gased with 95% O2-5% CO2, and kept at 37 degrees C. We measured RBCs concentrations by means of Coulter Counter in the venous outflow collected, and plotted them against the volume perfused. Using 2 different flow rates, 9 ml/min (group I) and 19 ml/min (group II), we found that the RBCs decreased in a multiexponential decay fashion and a biophysical model for each flow rate was constructed. These models indicated that there were more cell stores (2.20 x 10(10)) in the fast compartment of group II than in group I (1.72 x 10(10)). This difference is not statistically significant, but certainly coincides with urine flow collected from ureter cannula during perfusion. Our present data clearly suggest that in order to clear 99% blood cells out of 10-12 gm rabbit kidneys, at least 3-6 ml of cell free perfusate is required while clearing the whole blood cells out of human kidneys (200-240 gm) may need 600 ml or more. Thus, we recommend that at least 600 ml of perfusate should be used to clear most of the blood cells in the renal vasculature before renal transplantation is performed.

The use of a spectrophotometric assay to study the interaction of S-adenosylmethionine synthetase with methionine analogues

We have developed a continuous spectrophotometric assay for S-adenosylmethionine synthetase and, using this assay, have examined the interaction of five potential inhibitors with the E. coli enzyme. S-Vinylhomocysteine and S-allylhomocysteine were found to be substrates, while S-(methanethio)cysteine and S-(methanethio)homocysteine were found to be competitive inhibitors. S-Cyanohomocysteine is neither a substrate nor an inhibitor.

Acquired tufted angioma associated with pregnancy

Acquired tufted angioma is a distinctive condition that is different from other types of acquired vascular proliferation. Despite the progressive spread of these angiomas, they appear to be benign, and malignant change has not been encountered. We describe a case of recurrent acquired tufted angioma associated with pregnancy, an association which has not been previously recorded.

Simultaneous expression of keratin and glial fibrillary acidic protein by the same cells in epiretinal membranes

The identification of cells comprising epiretinal membranes is difficult because of the phenotypic changes that occur. Examination of intermediate filament protein content by immunocytochemical analysis can help to identify some cells with altered ultrastructure but is not always definitive because altered expression of intermediate filament proteins can also occur. To examine this issue further, the authors utilized a postembedding immunocytochemical technique with epiretinal membranes in which they were able to double label for keratin, a useful marker for identifying retinal pigment epithelial cells, and glial fibrillary acidic protein (GFAP), a useful marker for identifying glial cells. Nine of ten idiopathic epiretinal membranes contained cells that labeled for GFAP and not keratin. Two of these membranes also contained cells that labeled only for keratin and one membrane contained cells that simultaneously labeled for both GFAP and keratin. Other types of epiretinal membranes had an equal participation by cells that expressed only GFAP or keratin (12 of 17 membranes contained cells positive for keratin; 13 of 17 contained cells positive for GFAP). Ten of 17 nonidiopathic membranes contained cells simultaneously expressing GFAP and keratin, although they comprised only a minor subpopulation of the total number of cells present. These findings demonstrate that keratin and GFAP are not mutually exclusive intermediate filament proteins in cells of epiretinal membranes and that, although each may provide a helpful adjunct for cell type identification, neither is an absolutely specific marker.

Mutation creates an open reading frame within the 5' untranslated region of macaque erythrocyte carbonic anhydrase (CA) I mRNA that suppresses CA I expression and supports the scanning model for translation

A variant allele at the CA I locus that produces a deficiency of erythrocyte-specific CA I occurs as a widespread polymorphism in pigtail macaques from southeast Asia. Sequence analyses revealed a C----G substitution 12 nucleotides downstream of the cap site in the variant erythrocyte CA I mRNA. This mutation forms a new AUG start site and an open reading frame coding for 26 amino acids that terminates 6 nucleotides before the normal AUG initiation codon for CA I. It appears that the presence of this upstream open reading frame greatly diminishes reinitiation of translation from the normal start site, resulting in trace levels of CA I in erythrocytes. Preferential use of the first AUG codon supports the scanning model for translation initiation in eukaryotes.

Clinical application of arterialization of portal vein in living related donor partial liver transplantation

Arterialization of the portal vein was employed during hepatic arterial reconstruction in our first few clinical experiences of partial liver transplantation using liver grafts obtained from living related donors. This procedure reduced the time required for revascularization of the grafts to about 25 min, and could in fact reduce the ischemic phase of the grafts. Repeated practice of the clinical transplantation technique has shortened the time needed to complete vascular reconstruction, eliminating the need for this procedure in most of our subsequent cases. In many clinical cases, however, there may be emergency situations which require vascular reconstruction, resulting in a prolongation of ischemic phase and the deterioration of the cellular viability of the graft. In such situations, arterialization of the portal vein can be a useful way to prevent the prolongation of the ischemic phase and to rescue the graft.

[Comparative study on the effectiveness of modified Kato's cellophane thick smear and Stoll's dilution egg counting technique for quantitative fecal examination of helminth eggs]

A total of 197 fecal specimens was prepared for quantitative examination of helminth eggs by modified Kato's cellophane thick smear (M.C.T.S.) and Stoll's dilution egg counting technique (D.E.C.T.). The comparative effectiveness of two techniques was evaluated and conversion function was deduced. The average time required for the microscopic examination on one slide by M.C.T.S. was 12.6 minutes and that of D.E.C.T. was 14.6 minutes. M.C.T.S. showed lower false negative rate than D.E.C.T. in light worm burden cases. Functions to convert the counts obtained by M.C.T.S. to E.P.G. by Stoll's dilution egg counting technique were 47.86 x 10(0.87) logM.C.T.S. in A. lumbricoides, 41.69 x 10(0.82) logM.C.T.S. in T. trichiura and 63.10 x 10(0.85) logM.C.T.S. in C. sinensis. It was suggested M.C.T.S. be better than D.E.C.T. for the quantitative examination of intestinal helminthiases such as A. lumbricoides, T. trichiura, and C. sinensis infections even in the cases with low worm burden.

1,25-Dihydroxy-vitamin-D3 enhances antiproliferative effect and transcription of TGF-beta1 on human keratinocytes in culture

Both TGF-beta and 1,25-dihydroxy-vitamin-D3 (1,25(OH)2D3) have been reported to decrease the proliferation of normal human keratinocytes. The effect and expression of TGF-beta in keratinocytes treated with 1,25(OH)2D3 was investigated. Human keratinocytes were grown in the presence of various concentrations of TGF-beta and/or 1,25(OH)2D3 prior to enumeration. TGF-beta, alone, has a half maximal dose of inhibition (ED50) of approximately 750 pg/ml after seven days in culture in Keratinocyte Growth Medium (KGM; Clonetics) supplemented with 1.5 mM calcium. When 1,25(OH)2D3 (10(-7)M) was also added to cultures with various concentrations of TGF-beta, the ED50 shifted an average of 2-fold less. The presence of TGF-beta (10 pg/ml) augmented the potency of 1,25(OH)2D3 by at least 10-fold. In keratinocyte cultures, the antiproliferative effect of the two compounds together is synergistic. In keratinocytes grown for 1 week in the presence of 1,25(OH)2D3 at 10(-6)M, the TGF-beta 1 message increased approximately 5-fold. An increase is detected within 2 hours of exposure to 1,25(OH)2D3. There was only a 50% increase in the levels of TGF-beta 2 and no detection of TGF-beta 3. When keratinocyte cultures were treated with 1,25(OH)2D3 and neutralizing antibodies to TGF-beta, the induced-antiproliferative activity was blocked by more than 50%. The keratinocytes produced more active than latent TGF-beta after growth with high doses of 1,25(OH)2D3.

Compensation for three-dimensional detector response, attenuation and scatter in SPECT grey matter imaging using an iterative reconstruction algorithm which incorporates a high-resolution anatomical image

The use of SPECT to diagnose physiological alterations in disease states depends on the potential of SPECT to provide a quantitatively accurate reconstructed image. However, the reconstructed values depend upon the shape and size of the brain region as strongly as they depend upon true radioactivity concentration. We report here the results of applying an iterative reconstruction algorithm (IRA) to compensate for shape- and size-dependence, as well as for attenuation and scatter. The IRA is designed only for the reconstruction of images for which the true radioactivity in the white matter within the actual brain is negligible compared with the true radioactivity in the grey matter within the actual brain. The IRA incorporates an accurate three-dimensional model of detector response and utilizes an MRI image which defines the anatomical features of the brain being imaged by segmenting the grey, white and ventricular regions. It is the assumption of radioactivity localization exclusively in the grey matter which permits the efficient incorporation of the MRI image. The IRA was validated by simulation studies that utilized a slice through the basal ganglia in the realistic Hoffman three-dimensional mathematical brain model. FBP images deviate significantly from true radioactivity distribution, whereas IRA images are nearly identical to true radioactivity distribution, except for random fluctuations due to the presence of statistical noise. These results indicate that the application of the IRA will permit SPECT to distinguish deficits due to true physiological changes from apparent deficits due to imaging/reconstruction artifacts.

Homeostasis of sulfate and 3'-phosphoadenosine 5'-phosphosulfate in rats after acetaminophen administration

Acetaminophen (AA) is a drug whose biotransformation by sulfation is easily saturated. We have previously demonstrated in rats that its dose-dependent kinetics appear to be due to depletion of 3'-phosphoadenosine 5'-phosphosulfate (PAPS). In order to determine if the depletion of PAPS might be due to a lack of inorganic sulfate, we characterized the effect of AA not only on the homeostasis of PAPS but also on its precursor, sulfate. The maximum excretion of AA-sulfate was observed after 75 mg/kg of AA, i.p., and higher dosages did not increase its excretion. AA dosages between 150 to 600 mg/kg, i.p., 2 hr after dosing depleted 60 to 80% of hepatic PAPS. Hepatic PAPS levels returned to control values 16 to 20 hr after dosing with 600 mg/kg of AA. AA decreased serum sulfate to a similar degree (80%) and duration (16 hr) as did hepatic PAPS. AA also lowered sulfate concentrations in liver, but to a somewhat lesser extent (65%) than in serum. Hepatic sulfate levels returned to control values at 16 to 24 hr after dosing with AA. Even though AA did not alter renal PAPS concentrations, it did produce a 65% decrease in the renal sulfate levels. In summary, these studies demonstrate that AA markedly depletes PAPS concentrations in liver, but not in kidney, and drastically decreases serum and tissue sulfate concentrations. Our findings indicate that the capacity-limited sulfation of AA is due to the limited availability of hepatic PAPS, which in turn is limited by the availability of sulfate in liver.

Intraventricular neurocytoma: clinicopathological analysis of seven cases

A retrospective analysis of seven patients with intraventricular neurocytoma is presented. Patient age at diagnosis ranged from 15 to 38 years (mean 24.6 years) and the male:female ratio was 6:1. Raised intracranial pressure due to hydrocephalus was the main cause of the clinical manifestations. An isodense mass with multiple intratumoral cysts and homogeneous contrast enhancement was the characteristic computerized tomography finding. The lesions commonly involved the lateral ventricle with or without extension to the third ventricle. Cerebral angiography showed homogeneous vascular staining in five patients. Magnetic resonance images revealed a mass isointense with the cerebral cortex on both T1- and T2-weighted images. Gadolinium-diethylenetriaminepenta-acetic acid-enhanced images showed homogeneous enhancement. Total removal of the tumor was possible in four patients. Pathologically, six cases were initially diagnosed as oligodendroglioma and the remaining case as ependymoma. However, immunohistochemical studies demonstrated strong positivity for neuron-specific enolase in all seven cases and for synaptophysin in five cases. On electron microscopy, three cases showed well-defined neurosecretory granules and 10-nm microtubules in their cytoplasm and cytoplasmic processes. One patient developed a recurrent tumor 18 months after surgery. The remaining six patients are free of recurrent tumors at 2 to 62 months after surgery. It is suggested that neurocytoma must be included in the differential diagnosis of intraventricular lesions, and that electron microscopic and immunohistochemical studies should be undertaken.

Homeostasis of sulfate and 3'-phosphoadenosine 5'-phosphosulfate in rats with deficient dietary intake of sulfur

This study was designed to determine the role of dietary organic and inorganic sulfur on 3'-phosphoadenosine 5'-phosphosulfate (PAPS) homeostasis. Organic sulfur was altered by adding various amounts of methionine (0.15, 0.3, 0.6, or 1.2%) to a sulfhydryl-deficient diet. Inorganic sulfur was altered by providing rats with no sulfate or sulfate in their diets (0.12%) and distilled or tap water. Rats received these diets for 5 days. The two lowest methionine-containing diets produced a 60% reduction in liver glutathione concentrations, and the addition of sulfate to the diets did not restore hepatic glutathione levels. Urinary sulfate excretion was reduced by 95% in rats fed the three low-methionine diets. Addition of sulfate to these diets increased the urinary excretion of sulfate, but did not return sulfate levels to control values. The three low-methionine-containing diets decreased serum and liver sulfate concentrations about 50% and addition of sulfate to these diets largely restored them to control levels. Hepatic PAPS concentration was decreased (10%) only in the group receiving the lowest methionine content in their diet, and addition of sulfate had no effect on hepatic PAPS. In summary, dietary alterations of sulfur lowered the glutathione concentration in the liver as well as decreased sulfate levels in serum, liver, and urine, but had minimal effect on hepatic PAPS concentrations. Therefore, it appears that hepatic steady-state PAPS levels are not highly dependent on the sulfur content of the diet.

Effect of topical retinoic acids on the levels of collagen mRNA during the repair of UVB-induced dermal damage in the hairless mouse and the possible role of TGF-beta as a mediator

Topically applied retinoic acids have been found to enhance the gene expression for collagen types I and III in the skin of UVB-irradiated hairless mice. Prior damage is required because the effect is not observed in the skin of age-matched, non-irradiated control animals. Immunochemical methods have shown an increase in TGF-beta 1 and, to a lesser extent, of TGF-beta 2 in the epidermis following retinoic acid treatment. There were no changes in mRNA levels for any of the isotypes of TGF-beta induced by retinoic acid treatment. This study suggests that TGF-beta may mediate the effect of retinoic acids on dermal repair through the stimulation of collagen gene expression.

POEMS syndrome--a case report

POEMS syndrome is a multisystem disorder associated with polyneuropathy, organomegaly, endocrinopathy, a monoclonal protein (M-protein), and skin changes. The authors describe a patient with POEMS syndrome who had osteosclerotic myeloma confirmed by open bone biopsy. Magnetic resonance imaging (MRI) showed discrete lesions of low signal intensity in both T1 and T2-weighted images. This patient is now being successfully treated with melphalan and prednisone with much improvement in skin thickening and sensory change in the lower extremities.

Tissue sulfate determination by ion chromatography

The application of controlled-flow anion chromatography to assay inorganic sulfate in biological fluids and tissues is described. The eluent used in previous methods for analyzing sulfate in biological fluids has been modified by adding 4.5% acetonitrile to separate sulfate from a co-eluting peak. To markedly increase the life of the column, the tissue samples were further diluted, extracted with chloroform, and analyzed at a lower detection range (0.3 microS). The method has been shown to be applicable for determining sulfate in tissues as well as biological fluids.

Effect of phenylpropanolamine hydrochloride on blood pressure in Korean patients with hypertension controlled by hydrochlorothiazide

The effect of 10 oral doses of phenylpropanolamine hydrochloride 25 mg four times a day on blood pressure and heart rate in Korean patients with hypertension controlled by hydrochlorothiazide was studied. A randomized, placebo-controlled, crossover, double-blind study design was used. Twenty Korean patients with mild hypertension controlled by hydrochlorothiazide were recruited from an ambulatory-care clinic. Blood pressure and heart rate were measured in triplicate before treatment, after a five-day washout period between phases of treatment, and two hours after the last dose in each phase of treatment. Eighteen patients completed both phases of treatment, and one patient completed only the placebo phase. Mean baseline values for systolic and diastolic blood pressures and heart rate before the placebo phase did not significantly differ from mean baseline values before the phenylpropanolamine phase. Comparison of mean baseline values for systolic and diastolic blood pressures and heart rate with mean after-treatment values showed no clinically relevant or statistically significant changes for the 19 patients who completed the placebo phase or the 18 patients who completed the phenylpropanolamine phase. There was no significant difference between the mean change in systolic blood pressure, diastolic blood pressure, or heart rate when the phenylpropanolamine phase was compared with the placebo phase. Phenylpropanolamine hydrochloride 25 mg p.o. four times a day (total, 10 doses) given to Korean patients with hypertension controlled by hydrochlorothiazide did not affect blood pressure or heart rate according to single-point outcome measurements.

Heterogeneous changes of serum potassium levels in NIDDM patients on oral glucose load

Ten noninsulin dependent diabetic patients (NIDDM) without baseline hyperkalemia and with normal aldosterone levels when given 100 g of glucose orally revealed heterogeneous responses in serum potassium changes. Six diabetics had paradoxical increases in serum potassium levels averaged 0.44 mEq/L (range, 0.1 to 1.1 mEq/L) and were accompanied by increases in plasma aldosterone levels. On the contrary, four other noninsulin dependent diabetics and four nondiabetic control subjects had gradual decreases in serum potassium levels with simultaneous decreases in plasma aldosterone levels. These rises and falls in serum potassium concentrations coincided with changes in serum osmolality related mostly to the degree of increases in serum glucose following oral glucose administration. pH of venous blood didn't show any relevant and significant changes with changes of serum potassium levels following oral glucose load. This finding suggests that osmotic mechanisms with various degree of well known abnormal insulin secretion and resistance to insulin action in target tissues in NIDDM patients may account for these heterogeneous responses in serum potassium changes after glucose load, and normal aldosterone levels may not be sufficient to prevent glucose induced increases in serum potassium in NIDDM patients.

Pharmacokinetic simulations of SPECT quantitation of the M2 muscarinic neuroreceptor subtype in disease states using radioiodinated (R,R)-4IQNB

Alzheimer's disease (AD) involves selective loss of muscarinic M2, but not M1, subtype neuroreceptors in the posterior parietal cortex of the human brain. Emission tomographic study of the loss of M2 receptors in AD is limited by the fact that there is currently no available M2-selective radioligand which can penetrate the blood-brain barrier. However, by taking advantage of the different pharmacokinetic properties of (R,R)-[123I]IQNB for the M1 and M2 subtypes, it may be possible to estimate losses in M2. It has previously been hypothesized that the difference between an early study and a late study should provide information on the M2 receptor population. In order to test this hypothesis, we present here the results of pharmacokinetic simulations of the in vivo localization of (R,R)-[123I]IQNB in brain regions containing various proportions of M1 and M2 subtypes. These results permit us to conclude that SPECT imaging of (R,R)-[123I]IQNB localization can potentially be used to quantitate changes in the M2 subtype in a disease state within a brain region for which the ratio M2/M1 is sufficiently high in normal individuals.

3-D SPECT simulations of a complex 3-D mathematical brain model: effects of 3-D geometric detector response, attenuation, scatter, and statistical noise

The quantitative imaging characteristics of ultrahigh-resolution parallel-hole SPECT, including 3-D geometric detector response, attenuation, scatter, and statistical noise, were investigated by simulations based on a complex digitized 3-D brain model of the gray and white matter distributions. The projection data resulting from a uniform distribution of gray and white matter radioactivity, in a ratio of 5:1, were simulated. The results demonstrate significant qualitative and quantitative artifacts in reconstructed human brain images. In the absence of attenuation, scatter, and noise, artifactual variation caused inaccuracies in regional radioactivity quantification. Inclusion of attenuation scatter, and noise in the simulation caused additional artifacts, and resulted in reconstructed images which qualitatively and quantitatively corresponded very closely to reconstructed images of the actual 3-D brain phantom which was constructed from the same set of data as the mathematical 3-D brain model. It is concluded that the major degrading factor in SPECT neuroimaging is the 3-D geometric detector response function.

Magnetic resonance imaging in brainstem ischemic stroke

To evaluate the efficacy of magnetic resonance imaging in brainstem stroke, we studied 21 cases of clinically definite brainstem ischemic stroke with brain magnetic resonance imaging (MRI) and conventional computed tomography (CT). MRI demonstrated brainstem lesions in 79% of the cases (16.5 out of 21), while CT revealed 33% (7 out of 21) when cases with suspicious lesions counted as 0.5. Although MRI was done a few days later than CT in most cases, MRI was superior to CT in detecting the number and the size of ischemic lesions, with clear delineation of anatomy and visualization of the status of the blood flow in the vertebral-basilar artery. Disappearance of the flow signal void in the basilar artery can be an important clue in diagnosing occlusion or thrombus of the basilar artery. By delineating the extent and the location of the infarction, MRI findings allowed an interpretation of whether the ischemic vessel is a small basilar branch or a large vessel vertebral or basilar artery.

Three-dimensional SPECT simulations of a complex three-dimensional mathematical brain model and measurements of the three-dimensional physical brain phantom

We have developed a three-dimensional computer simulation of SPECT imaging. We have applied the simulation procedure to the realistic mathematical Hoffman three-dimensional brain model to generate the projection data (in the absence of attenuation, scatter, or noise) of both a parallel-hole and a multidetector SPECT system with point-focusing collimators. The simulated projection data were then reconstructed using standard software. The projection data resulting from the distribution of grey matter alone, or grey and white matter, were simulated. The results of these simulations indicate the existence of significant qualitative and quantitative artifacts in reconstructed human brain images. For example, the reconstructed values for grey matter along a cortical circumferential profile in a transverse slice through the basal ganglia varied by a factor of 2.40 (parallel-hole) and 2.99 (point-focusing), although the original grey matter values were identical in all cortical regions in the model. We have compared the simulated reconstructed images with those obtained by imaging the physical three-dimensional Hoffman brain phantom, which was constructed based upon the same set of data from which the mathematical three-dimensional Hoffman brain model was derived. Although the simulation did not include all of the degrading factors present in the physical imaging, the two images were in good agreement, indicating the applicability of the simulation to a realistic situation and the importance of the detector resolution effect.