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Biomedical subjects

M B Johnson

Publications and source records attributed to M B Johnson.

At least 19 recordsLinked to original sources
PubMed1992

Familial omphalocele: considerations in genetic counseling.

Nonsyndromal omphalocele is generally regarded as a sporadic malformation. Recurrence risk is considered negligible. We report on a patient in whom 5 consecutive pregnancies (by 2 separate nonconsanguineous partners) were complicated by omphalocele as an isolated defect. Neither the patient nor her partners had history of relatives with omphalocele, although the patient's brother and his son had large umbilical hernias requiring repair in infancy. Some familial cases of nonsyndromal omphalocele have been previously reported; most such pedigrees suggest vertical transmission, although there are a few cases with only a single generation involved. In our case, the multigenerational finding of ventral wall hernias makes an autosomal dominant mechanism with variable expressivity a tenable explanation. The collected instances of familial nonsyndromal omphalocele emphasize omphalocele heterogeneity and caution in counseling recurrence risks.

Female↗
PubMed1992

Uncomplicated amebic liver abscess: prospective evaluation of percutaneous therapeutic aspiration.

The performance of therapeutic aspiration in the treatment of amebic liver abscess, advocated and practiced in many centers, is controversial. Previously, this practice has been evaluated in retrospective analyses. To test the potential benefit of therapeutic aspiration, the authors undertook a prospective randomized trial in 57 patients admitted for suspected amebic liver abscess during a 15-month period. Sixteen patients were excluded from the trial. The remaining 41 patients were randomly included in one of two study groups to receive amebicidal therapy alone or amebicidal therapy coupled with image-guided percutaneous therapeutic aspiration. All patients in the trial recovered. No statistically significant benefit was demonstrated in the aspiration group for the two objective parameters evaluated: length of hospitalization and duration of time to becoming afebrile. Subjective improvement in symptoms after aspiration was greater in the aspiration group at a marginally statistically significant level. These data do not support the adjunctive performance of percutaneous therapeutic aspiration in the treatment of uncomplicated amebic liver abscess. Amebicidals alone were equally efficacious in treating the group studied.

Humans↗
PubMed1992

Budd-Chiari syndrome: detection with color Doppler sonography.

The value of color Doppler sonography in evaluating newly diagnosed Budd-Chiari syndrome in five patients was studied. Hepatic venous findings included absence of vessels (one patient), flow reversal (two patients), narrowing (four patients), and tortuosity (three patients). Detected collaterals included hepatic venous to hepatic venous (four patients), hepatic venous to subcapsular systemic venous (two patients), and portosystemic (three patients). Hepatic venous spectral Doppler waveforms were flat and essentially aphasic in four patients, indicative of distal hepatic venous compression. The inferior vena cava was markedly compressed in two patients and slightly compressed in one. Color Doppler sonography allowed more reliable and confident identification of irregular, compressed, or otherwise abnormal hepatic veins than did conventional sonography. Color Doppler sonography also showed collateral vessels that were undetected with conventional sonography or other imaging techniques. Our results suggest that color Doppler sonography may be a valuable tool in the initial diagnosis and evaluation of suspected Budd-Chiari syndrome.

Budd-Chiari Syndrome↗
PubMed1991

Splenic salvage vs splenectomy. Care of the trauma patient.

Because of the incidence of overwhelming postsplenectomy sepsis that occurs after splenectomy, there is an increased incentive to try to salvage the spleen in patients with splenic injury. Even though operative time is increased by this technique, the advantage of immunologic competence is well worth the added operative time. In hemodynamically unstable patients, however, splenectomy remains the method of choice.

Hemostatics↗
PubMed1991

Portal venous system after portosystemic shunts or endoscopic sclerotherapy: evaluation with Doppler sonography.

We sought to determine the usefulness of duplex Doppler sonography in the assessment of blood flow and clot formation in the portal vein in 44 patients with portal hypertension and bleeding esophageal varices who had undergone either endoscopic sclerotherapy (28 cases) or portosystemic shunt procedures (16 cases). The main, left, and right portal veins (collectively referred to as intrahepatic portal veins), superior mesenteric vein, splenic vein, and shunt were assessed for flow direction, presence of thrombi, and collaterals. Patent shunts were visualized in 12 (75%) of the 16 cases. Clot was detected in 27 (69%) of 39 intrahepatic portal veins in patients with end-to-side shunts, in six (67%) of nine intrahepatic portal veins in patients with distal splenorenal shunts, and in five (5%) of 92 intrahepatic portal veins in patients who had had endoscopic sclerotherapy. Flow in the main portal vein was hepatopetal in two (15%) of 13 patients with patent shunts (one end-to-side portacaval shunt and one distal splenorenal shunt). Flow in the main portal vein was hepatopetal in 26 (93%) of 28 patients who had had endoscopic sclerotherapy. Our data suggest endoscopic sclerotherapy preserves antegrade portal flow and results in fewer portal vein clots than surgical portosystemic shunts do. Patterns of thrombosis and flow direction vary unpredictably from patient to patient. Shunt patency should not be inferred without direct visualization of the shunt.

Esophageal and Gastric Varices↗
PubMed1991

Color Doppler sonographic findings in renal vascular lesions.

Three patients with renal vascular lesions, one congenital arteriovenous (AV) fistula and two renal pseudoaneurysms, were assessed with color Doppler sonography. The AV fistula was detected initially by color Doppler after having been missed by both real-time sonography and computed tomography. High frequency shift blood flow within a hypoechoic lesion noted by color Doppler characterized the AV communication. Both renal pseudoaneurysms had detectable bidirectional swirling blood flow within an anechoic portion of a complex mass. Findings in all three cases were confirmed by angiography or pathology. Color Doppler sonography seems potentially useful in the evaluation of renal vascular pathology.

Adult↗
PubMed1991

Color Doppler sonography in hepatocellular carcinoma.

Sixteen patients with hepatocellular carcinoma (HCC) were assessed with color Doppler sonography (CDS) for flow compared to normal hepatic parenchyma. Nine showed moderate increased flow, and two revealed marked increased flow. In most instances, the increased flow was peripheral. Color Doppler was also useful in assessing seven patients with portal vein invasion. In two instances, venous invasion was not detected on preliminary grayscale images. In another patient, hepatic venous invasion was suspected on grayscale images, but was shown to represent extrinsic compression only by color Doppler.

Carcinoma, Hepatocellular↗
PubMed1991

Color Doppler sonography of the scrotum.

Color Doppler sonography is a noninvasive, rapidly performed, and relatively inexpensive imaging technique for use in the diagnosis of scrotal pathology. Its major and proven role is in the evaluation of patients with acute scrotal pain, for which it is likely to become the primary imaging modality. Further work is needed to determine whether color Doppler is a useful diagnostic adjunct in evaluating patients with varicoceles and scrotal masses.

Doppler Effect↗
PubMed1990

Color Doppler sonography in acute epididymitis and orchitis.

Clinical diagnosis of patients with acute scrotal pain is frequently imperfect. Imaging, using nuclear medicine scintigraphy and hand-held continuous-wave Doppler ultrasound devices, has been used in these patients. We retrospectively analyzed 28 consecutive patients referred for scrotal sonography, all of whom had been imaged using color Doppler sonography. Of 22 patients with confirmed diagnoses, 11 had acute epididymitis/orchitis and 11 had another diagnosis. Ten of 11 patients with acute epididymitis/orchitis had increased epididymal flow. Eight also had increased testicular flow. None of the 11 patients without acute epididymitis/orchitis had increased flow. Our data suggest that color Doppler sonography may be useful in establishing the diagnosis of acute epididymitis/orchitis. This might decrease the need for scrotal exploration. No distinction could be made among scrotal lesions in the nonacute epididymitis/orchitis group. Sensitivity was inadequate to reliably detect flow in normal testicles, a prerequisite to accurately diagnose torsion. Newly improved sensitivity may enhance the utility of color Doppler sonography in assessing patients with acute scrotal pathology.

Acute Disease↗
PubMed1990

The holistic paradigm in nursing: the diffusion of an innovation.

Nursing today is affected by challenges to the beliefs and values underlying the delivery of health care services. Results of a bibliometric analysis of the nursing literature since 1966 revealed a process of paradigm change in which a scientific medical model is being replaced by a model based on the concept of holism. Key ideas representing a holistic paradigm of health appear with increasing frequency in the journals of the nursing field, demonstrating the diffusion of a new and different perspective in the practice of nursing.

Bibliometrics↗
PubMed1990

The effects of prior exposure to silicone on capsule formation, histology, and pressure.

Investigations into the effects of prior silicone exposure on subsequent capsule formation around silicone implants assume particular relevance in light of the exponential increase in the medical application of polymers such as silicone. The inert nature of silicone has been in question with regard to its effects on the immune system, specifically whether or not it may act as a hapten or antigen. The present study analyzes the effects of prior silicone exposure on subsequent capsule formation, histological consistency, and pressures when an animal is reexposed to a silicone implant. Twelve female Lewis rats (body weight 250 g) were randomly divided into two groups. Group 1 (n = 6) rats were subcutaneously injected with 2.5 ml of Freund's Complete Adjuvant, Group 2 (n = 6) rats were injected with an equal volume of adjuvant sonicated with silicone gel. At 4 weeks a gel-filled silicone implant was placed subcutaneously in each animal. Capsule pressures were obtained at 4 months and the capsules from 3 rats from Group 2 were excised and examined microscopically. Pressures were measured again at 8 months and all remaining capsules were excised and examined. No statistically significant differences were noted when comparing two profiles over time between silicone-exposed and nonexposed animals in regard to capsule thickness or capsule pressure. However, capsule pressures were significantly lower at 8 months than at 4 months in both groups (p less than 0.034). In this model, significant reductions in capsule pressure were noted in both groups over time, but prior exposure to silicone did not appear to alter capsule histology, thickness, or pressure.

Animals↗
PubMed1990

Assessment of the lymphocyte response to silicone.

The biocompatibility of silicone is once again the focus of increased interest. Long considered inert, silicone has now been reported to be responsible for macrophage inhibition in rats and to possibly cause adjuvant disease in humans, and the related compound silica has elicited an antibody response in mice. The present study evaluates lymphocytic response to silicone as expressed by the demonstration of immunologic memory, or changes in specific lymphocyte subpopulations. Thirty-six female Lewis rats (250 gm body weight) were used as test animals. Group 1 (n = 12) was injected subcutaneously with 2.5 ml Freund's Complete Adjuvant (FCA) alone. Group 2 (n = 12) was injected with 2.5 ml FCA sonicated with silicone gel. Group 3 (n = 6) was injected with 2.5 ml FCA, and at 4 weeks, gel-filled silicone implants were placed subcutaneously. Group 4 (n = 6) was injected with 2.5 ml FCA sonicated with silicone gel, and gel-filled silicone implants were placed at 4 weeks. An additional group of six rats (group 5) served as control for the experimental animals, and a group of four rats (group 6) served as naive control. Groups 1 and 2 were sacrificed at 4 weeks, and splenic lymphocytes were obtained for lymphocyte transformation assays performed against silicone. Assays also were run with the addition of the known mitogens Con A, PHA, LPS, and pokeweed. Cytofluorographic analysis of pan-T, T-helper, T-suppressor, and B-cell populations was performed. Groups 3, 4, 5, and 6 were harvested at 8 months, and splenic lymphocytes were subjected to lymphocyte transformation assay.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Pulsed Doppler sonography of the hepatoduodenal ligament: efficacy and ease of performance.

A prospective analysis of the hepatoduodenal ligament (HDL) in 205 patients with abdominal pulsed Doppler sonography supports the conclusion that Doppler ultrasound is a useful adjunct to routine scanning in this area. Abdominal pulsed Doppler sonography allows reliable differentiation among the HDL structures by identifying and characterizing flow in the portal vein and hepatic arterial structures, while demonstrating no flow in the bile ducts. Proper hepatic arterial signal was obtained in 190 (92.7%) patients. Portal venous signal was obtained in virtually all (203 of 205-99%) patients. Abdominal Doppler sonography shows promise in its ability to provide definitive diagnostic information in situations where images alone may prove misleading. Doppler sonography can differentiate similarly sized bile ducts and arteries and detect dilated arterial and venous structures simulating dilated bile ducts.

Common Bile Duct↗
PubMed1988

FM sonography in gallbladder disease: efficacy and comparison with conventional sonography.

A new type of ultrasound signal processing ("FM sonography") appears to be beneficial compared to conventional ultrasound ("AM sonography") in some applications (e.g., diffuse liver disease and prostatic carcinoma). Despite these possible advantages, it is doubtful FM sonography will be widely used unless it is at least as useful as conventional (AM) sonography in all common applications. Fifty-five patients with suspected gallbladder disease were independently evaluated with both AM and FM sonography. The two modalities were blindly and prospectively compared for accuracy in detecting gallstones and for image quality. No statistically significant difference was found between images produced by FM and conventional signal processing. FM had an accuracy of detecting gallstones of 98.1%, compared to 96.2% for AM. Overall, FM accuracy was 97.7%, while AM had an overall accuracy of 97.3%. Other useful sonographic signs were evaluated (gallbladder wall thickness, diameter of common duct). No AM/FM difference was noted. Our data suggest that FM-only imaging could be performed in patients with suspected gallbladder disease without loss of accuracy.

Cholelithiasis↗