The importance of congenital hypertrophy of the retinal pigment epithelium in familial adenomatous polyposis

We describe a family with familial adenomatous polyposis (FAP) and congenital hypertrophy of the retinal pigment epithelium (RPE). Three of five members with FAP showed flat, well-demarcated, round to oval pigmented patches of congenital hypertrophy of the RPE. We stress the importance of congenital hypertrophy of the RPE as a clinical marker in identifying patients with FAP since they are at risk for cancer.

The inlet patch: heterotopic gastric mucosa in the upper esophagus

Careful endoscopic survey of the upper esophagus indicates that a visually recognizable patch of gastric mucosa is grossly visible much more commonly than is generally recognized. Sixteen instances were found in 420 sequential endoscopies, an incidence of 3.8%. The gastric mucosal rest presented as a velvety red patch with a distinct border, varying from a few millimeters in diameter to complete encirclement of the esophagus, was occasionally paired, and was found either at or just below the upper esophageal sphincter. In all instances except one the patch consisted of gastric-type mucosa containing both parietal and chief cells; in the single exception, it consisted of gastric-type mucous glands without parietal cells. Although larger patches can be shown to function under stimulation (they produce a local drop in pH with pentagastrin stimulation), there are usually no apparent associated clinical symptoms.

A comparison of tube leukocyte adherence inhibition assay and standard physical methods for diagnosing colorectal cancer

In vitro antitumor immunity, measured by means of a tube leukocyte adherence inhibition (LAI) assay, was able to demonstrate early colorectal cancer in cases yet undiagnosed. Testing 106 patients attending a colonoscopy clinic, we found that nine of 15 (60%) patients with colorectal cancer were LAI-positive. The nine included: five of six with Dukes' A and B; one of two with Dukes' C; and three of seven with Dukes' D lesions. Of 58 patients without colon neoplasia, one had a positive test. By contrast, barium enema results were diagnostic for 13 of 15 (87%) cases and colonoscopy for 11 of 15 (73%). There were 32 colon polyps discovered by means of barium enema and colonoscopy. Of 13 adenomas removed, four had stimulated positive LAI responses. Of another 19 polyps not removed two incited positive LAI responses. Two patients with histories of recurrent adenomas were LAI-positive, though only one had a new polyp that could be detected by means of barium enema. For a procedure to be of diagnostic value for a given disease, sensitivity and specificity must be at least 1.0. If this sum is 2.0, the test is ideal. The sum of sensitivity and specificity for the tube LAI assay, barium enema, and colonoscopy were 1.58, 1.87, and 1.73, respectively, for colorectal cancer; 1.81, 2.0, and 2.0, respectively, for early colorectal cancer; and 1.42, 1.77, and 1.55 respectively, for advanced colorectal cancer. In this limited series of patients, the barium enema seems to be superior to the tube LAI assay for diagnosing colorectal cancer, but the difference in sensitivity and specificity is not statistically valid by the paired chi square test. The results of this study shows conclusively, that the tube LAI is of diagnostic value and suggest its use for evaluating suspected cases, especially early ones, of colorectal cancer.

Nondestructive determination of pacemaker sense amplifier passband

Most artificial cardiac pacemakers incorporate sense amplifiers to detect intrinsic heart activity in order to eliminate the possibility of competition between the artificial and natural pacemakers. When artificial pacemakers fail prematurely, the failure cause should be determined so that systematic failure modes can be identified and corrected. The failure analysis of any sophisticated electronic product is difficult; failure analysis of a cardia pacemaker is complicated by the sealing technologies encountered. Because access to the circuitry of implantable devices is impeded by the packaging of the device, and because the packaging may have influenced the failure, nondestructive testing techniques must be used extensively. This paper reports on a method for nondestructive determination of the pacemaker sense amplifier with a (sin x)/x waveform to which a continuous wave sinusoid is added. The amplifier passband is characterized by increasing the frequency of the sinusoid in increments of 5 Hertz and determining the amplifier sensitivity at each step.

Neurofibromatosis and hyperparathyroidism--a new syndrome?

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Immunoglobulin synthesis in vitro by human thymus: comparison of myasthenia gravis and normal thymus

Immunoglobulin synthesis measured in incubated thymus tissue by the incorporation of [¹⁴C]amino acids has been studied in four thymus glands from patients with myasthenia gravis and in eight normal thymus glands from patients undergoing open heart surgery. Parallel studies have been carried out with one normal human spleen and two lymph nodes.

Thymus tissues from patients with myasthenia gravis incorporated an average of twice as much radioactivity into soluble protein on a wet weight basis as normal thymus tissues. On the same basis, they synthesized approximately six times as much immunoglobulin as the normal thymus, emphasizing the association of an abnormal immune response in the thymus with this disease.

Comparison of incorporation of [¹⁴C]amino acids into immunoglobulin showed that on a wet weight basis the normal lymph nodes studied synthesized a mean of twenty-five times, and the normal spleen, six times as much immunoglobulin as the normal thymus. Thus, these studies establish that the normal as well as the hyperplastic thymus gland shares with peripheral lymphoid tissue the capacity to produce immunoglobulin.

Preliminary studies of the antibody specificity of a purified fraction of [¹⁴C]IgG from myasthenia gravis and normal thymus have shown no reactivity of thymic IgG with normal human thymus or muscle by radioautographic and immuno-fluorescent techniques.