Some thoughts on the future of clinical trials groups in cancer.
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Biomedical subjects
Publications and source records attributed to M Shapiro.
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The role of the hippocampus in memory processing was examined by recording single unit activity while rats performed two different types of memory tasks. The same apparatus was used for all tasks; it consisted of two goal boxes, side by side, on the end of a runway. One goal box was white, the other was black. Experiment I used a working memory, delayed match-to-sample (DMTS) task. A trial began with a sample phase in which the rat was forced to a goal box containing a reward. The rat was then placed at the beginning of the runway again for the choice phase and allowed to enter either of the two goal boxes. Entering the goal box with the same color as that entered during the sample phase was rewarded. Experiment II used a within-subjects, within-units, design to test rats in two reference memory tasks, a cue task and a spatial task. During the cue task, the rat was rewarded for choosing the same colored goal box on each trial regardless of its spatial location. During the spatial task, the rat was rewarded for choosing the goal box in a specific location on each trial regardless of its color. During all tasks, the location of the goal boxes was changed between trials in a pseudorandom, counterbalanced fashion so that each colored goal box was on the right for half of the trials and on the left for half of the trials. During performance of the DMTS task, activity of most units was correlated with a combination of factors such as color and location, or color and phase. For example, most units showing differential activity in one of the colored goal boxes fired more when that box was in a certain spatial location, or during either the sample or choice phase. During performance of the reference memory tasks, the activity of most units was not correlated with behavior. However, the rate for some units changed between the cue and spatial tasks. When unit activity was correlated with behavior, it was dependent on a combination of dimensions such as color and spatial location. These results demonstrate that units in the hippocampus respond to combinations of stimulus dimensions such as color and spatial location, and to the temporal context necessary to solve a working memory task.
The petrosquamosal suture and septum are formed at the junction of the petrosal and squamosal bones. The suture crosses the temporal bone obliquely in an anteroposterior direction. Anteriorly, its anatomy is complex due to the convergence of two other bones: the sphenoid and the tympanic. Posteriorly, the petrosquamosal (Körner's) septum has a distinctive appearance on computed tomography (CT). While the anterior attachment of the septum can be used as a guide during surgery, the surgeon must also be aware preoperatively that large septa on CT can be mistaken for the medial mastoid wall. Prior to CT, Körner's septum has been used as a roentgenographic landmark to determine cholesteatoma extension. We now propose that the septum can also be used as a gauge for squamomastoid sclerosis.
A randomized, placebo-controlled, double-blind and sequentially analysed clinical trial to determine the efficacy of intra-operative parenteral gentamicin and vancomycin (with streptomycin in the irrigating solution) in preventing infection at the operative site following neurosurgical procedures is described. Patients receiving prophylaxis had a significantly (P = 0.046) lower operative site infection rate (2/71 = 2.8%) than those receiving placebo (9/77 = 11.7%). This difference was most apparent during an epidemic, the source of which was not evident. Moreover, a total of 13 infections (two operative site, five pneumonia and six urinary tract) occurred among 12 patients receiving prophylaxis, whereas there was a total of 31 infections (nine operative site, nine pneumonia, 10 urinary tract and three septicaemia) among 24 patients receiving placebo. A smaller quantity of antimicrobial drugs was administered postoperatively to patients receiving prophylaxis (3.96 'antibiotic-days' per patient) than to those receiving placebo (6.87 'antibiotic-days' per patient).
A previously healthy 61-year-old woman was seen with an abnormal chest roentgenogram and a 3-week history of fever, chills, malaise, and right upper quadrant pain. Blood cultures revealed Pasteurella multocida sensitive to penicillin. Liver spleen radioisotope scan and CT scan revealed space occupying lesions in the right lobe of the liver. The patient was a gardener with no pets or animal exposure. This case illustrates P. multocida septicemia and a liver abscess in a patient without animal exposure. In addition, the possibility of soil as another reservoir of infection is raised.
The ability to breathe spontaneously through an endotracheal tube is a usual prerequisite before an intubated patient can have it removed. Other researchers have measured air flow resistance through endotracheal tubes. In this study, we evaluated work of breathing in joules per min and tension-time index while three normal volunteers breathed through different sized endotracheal tubes. Four 27.5-cm endotracheal tubes were used. Subjects breathed with a constant tidal volume of 500 ml. By increasing respiratory frequency, minute ventilation was increased from 5 to 30 L/min. As tube diameter decreased, work and the tension-time index increased. Changes were magnified at higher minute ventilations through the 6- and 7-mm endotracheal tubes, and the tension-time index critical fatigue level of 0.15 was approached or exceeded.
Two chimpanzees immunized with woodchuck hepatitis virus (WHV) surface antigen (WHsAg) developed antibodies cross-reactive with hepatitis B virus (HBV) surface antigen (HBsAg). After challenge with HBV, one animal was completely protected and the other experienced a subclinical infection, without evidence of liver disease. Three woodchucks immunized with HBsAg developed antibodies to HBsAg which did not cross-react with WHsAg. After challenge with WHV, all three woodchucks developed typical acute infections with associated hepatic lesions. Serological studies with the cross-reactive antibodies raised in chimpanzees suggested that the protective epitopes of WHsAg were related to the group a specificity of HBsAg. These studies indicated that cross-protective epitopes are shared by HBV and WHV; however, the humoral response to these epitopes can vary among species.
Three-dimensional (3D) images were reconstructed from axial computed tomographic scans using the new 3D83 (General Electric Co.) software. Images were reformatted as a movie in multiple frames, each consisting of a discrete 3D scene, and were rotated 360 degrees in 3D space. Improvement in shading and surface algorithm has been made from the previous 3D82 program so that 3D images now have a realistic appearance. Soft tissue and bone modes are available; the latter reconstructs best in 3D because of its high density pixels, which provide a more exclusive threshold. 3D reconstructions of the spine were the most rewarding because the complex anatomy of the spine seems to be best suited for 3D imaging. By hemisection of the spine by subregion, the intervertebral foramina can be evaluated for stenosis. Some drawbacks in this program are the need for user interaction, the lengthy time of reconstruction, and the dependence on high quality axial images.
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Two experiments investigated whether a species of songbird perceives missing fundamentals in sounds containing complex frequencies. In Experiment 1, European starlings were trained to discriminate between two sinusoids. This discrimination persisted when the sinusoids were replaced with waveforms composed solely of four consecutive higher harmonics of the training frequencies. In Experiment 2, starlings trained to discriminate between two complex frequencies consisting of sets of higher harmonics transferred the discrimination to the sinusoidal fundamentals. The results demonstrate that starlings can perceive harmonic or periodic structure, and show that a species of songbird can use harmonic structure to gain information about its auditory environment. The findings, together with those obtained from fish and mammals, suggest that periodicity pitch perception may be a general process in vertebrate hearing.
Fifty patients with drug-refractory (failed 7 +/- 2 other drug trials) sustained ventricular tachycardia or fibrillation were treated with oral lorcainide. Twenty-three patients underwent programmed stimulation both before and after oral lorcainide, and all 23 remained inducible, although ventricular tachycardia cycle length was prolonged and mean arterial pressure was higher. Lorcainide was discontinued in 23 patients prior to hospital discharge because of death in four patients, side effects in five patients, spontaneous clinical arrhythmia recurrence in six patients, and ventricular tachyarrhythmias induced at electrophysiologic study in eight patients. Twenty-seven patients were discharged on an average dose of 169 +/- 56 mg twice a day, including 15 in whom ventricular tachycardia remained inducible. During long-term follow-up the drug was discontinued in 15 patients; three because of side effects, three because of clinical nonfatal arrhythmia recurrence, two who selected other alternative therapy, and seven patients who died suddenly due to ventricular tachyarrhythmias. Twelve patients remain on long-term lorcainide. The actuarial 1-year chance of being arrhythmia free was 38.9%, and 1-year cardiovascular and arrhythmia survival rates were 56.8% and 60.4%, respectively. Based on our data we conclude that: In this extremely drug-resistant patient population the clinical efficacy of lorcainide is low; lorcainide should not be used empirically in such highly drug-resistant patients; persistent ventricular tachyarrhythmia inducibility at electrophysiologic study implies a poor prognosis in patients treated with oral lorcainide; the incidence of becoming noninducible during oral lorcainide therapy in highly drug-resistant patients appears low; and for patients in whom the drug seems partially beneficial it could be used in conjunction with a backup automatic implantable cardioverter/defibrillator.
Solid-phase radioimmunoassays for woodchuck hepatitis virus core antigen (WHcAg) and antibody (anti-WHc) were developed. WHcAg in woodchuck liver homogenates was characterized by ultracentrifugation in CsCl gradients; both heavy (1.35 g/cm3) and light (1.31 g/cm3) cores were obtained from the liver of an animal during acute WHV infection, which is consistent with observations in hepatitis B virus infection in man. Endpoint titers of anti-WHc were higher in chronic WHV carriers than in animals recovered from acute infections. Both IgM and IgG anti-WHc antibodies were produced by infected woodchucks. A survey of colony woodchucks demonstrated that 88/89 animals having one or more markers of past or ongoing WHV infection were positive for anti-WHc. Thus, serum anti-WHc appears to be a sensitive marker of WHV infection.
The evolution of lacquer cracks is documented by serial fundus photography and fluorescein angiography in a 27-year-old man with high myopia. The case report provides some insight into the possible pathogenic mechanism of lacquer crack formation.
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We have examined effects of an autosomal gene on the expression of serologically detectable H-Y, a male-specific minor histocompatibility antigen for which a role in primary sex determination has been postulated. Quantitative immunoabsorption studies using three different male specific antisera revealed variation in the level of H-Y among inbred mouse strains and mice bearing variants of the T/t complex. Two patterns of expression in inbred strains were observed; high, C57BL/6J (B6) and low, which included A/J (A), C3H/ DiSn and DBA/2J. In F1 hybrids between A (female parent) and B6 (male parent), the F1 expressed H-Y levels indistinguishable from A, the low parent. Among T/t complex variants, mice bearing T or t0 showed high expression whereas those of the t12 haplotype showed low expression. The co-segregation of H-Y expression types with these T/t complex variants provided further evidence for the location of a gene determining the level of H-Y antigen on the proximal portion of chromosome 17.
In a prospective study of 376 orthopaedic patients, the relative contribution of host factors and patient-care variables to the risk of postoperative wound infection was evaluated. Host factors studied were age, sex, ethnic origin and diagnosis. The number of operations, the insertion of an open drain, the use of prophylactic antibiotics and the length of the operation were the patient-care variables studied. Of the risk factors identified, the performance of more than one operation during an admission had the highest risk coefficient, followed by the presence of an open drain, internal fixation of a fracture, and spine fusion. Within the group of operations for internal fixation, those for fractures of the femur had the highest risk of infection. In spine fusions those operations lasting 5 or more hours were associated with a high risk of infection. The length of stay of infected patients was on average 17.9 days longer than that of their individually-matched non-infected controls.
We randomized 58 women with lower urinary tract infection diagnosed on bilateral ureteral catheterization studies to a 1-day or 10-day treatment regimen. The study revealed that 1-day adequate antibacterial treatment was as effective as 10-day treatment for lower urinary tract infection. Sterile urine was obtained in all 27 women (100 per cent) given 1-day treatment and in 30 of 31 (97 per cent) given 10-day therapy. Three weeks after the 1-day treatment significantly more postmenopausal women had infected urine than premenopausal women. This difference was not seen in the 10-day group. We conclude that 1-day treatment is sufficient for the cure of lower urinary tract infection in women.
Neuronal ceroid lipofuscinosis, also known as the Batten-Vogt syndrome, is clinically manifested by seizures, loss of intellect, and deterioration of vision. The retinal histopathologic and ultrastructural changes have been well-described. This report adds the findings of trypsin digest preparation of the retinae in three such patients with varying duration of this disease. Acellular retinal capillaries, or ghost vessels, were observed, and the degree of this change correlated with the duration of clinical symptoms. These changes, as well as the histopathologic abnormalities, are discussed.