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M Hertz

Publications and source records attributed to M Hertz.

At least 37 records · Page 2Linked to original sources
PubMed2001

CT findings of the chest in adults with aspirated foreign bodies.

The aim of this study was to assess the imaging findings in adult patients with tracheobronchial foreign body aspiration. Nineteen patients (11 men and 8 women; age range 26-89 years) with foreign-body aspiration were retrospectively reviewed. Nine patients were outpatients with non-specific symptoms and ten were hospitalized with nonresolving pneumonia (n = 6), after detection of a dental fragment on a chest radiograph following intubation (n = 3), and there was one mentally retarded patient with empyema. An aspirated dental fragment was seen on a chest radiograph in 3 patients and an endobronchial foreign body on CT in 16, appearing as a dense structure within the bronchial lumen. The foreign body was right sided in 14 cases and left sided in 5. Three cases were missed at first interpretation. Associated findings on CT were volume loss, hyperlucency with air trapping and bronchiectasis in the affected lobe. Thirteen patients were managed with bronchoscopy, whereas 2 needed thoracotomy. In 1 patient bronchoscopy failed to detect a foreign body, indicating a false-positive CT diagnosis. One patient expelled an aspirated tablet and two refused invasive procedure. The foreign bodies found mainly were bones and dental fragments. A high clinical suspicion is necessary to diagnose a foreign body. Since CT is often used to evaluate various respiratory problems in adults, it may be the first imaging modality to discover an unsuspected aspirated foreign body in the bronchial tree.

Adult↗
PubMed2001

Renal duplication with associated complications in adults: CT findings in 26 cases.

AIM: To review the computed tomography (CT) findings in 26 adult patients with complicated renal duplication, and to assess whether the complications were anomaly-related or superimposed by acquired disease. MATERIALS AND METHODS: Fifteen women and 11 men, aged 17-83 years took part in the study. All CT studies were reviewed to define the moieties affected. RESULTS: The duplication was unilateral in 18 cases and bilateral in six, one patient had a single left kidney and the remaining one a horseshoe kidney. In 14 patients the pathology was related only to the anomaly. Upper pole abnormalities were seen in 13 patients (seven related to the anomaly) and lower pole abnormalities in five (all related to duplication). Both systems were affected in eight cases, six of them by pathological processes unrelated to duplication. Hydronephrosis of the affected collecting system was the most common imaging finding. CONCLUSION: Computed tomography is often used to evaluate abdominal conditions in adults and may therefore be the first imaging modality to reveal a duplex kidney complicated by a pathological process. Involvement of only one moiety was frequently related to the duplication, with a predilection for the upper moiety, while involvement of both systems was used unrelated to the duplication. Zissin, R. (2001). Clinical Radiology, 56, 58-63.

Adolescent↗
PubMed2001

Primary serous papillary carcinoma of the peritoneum: CT findings.

AIM: To describe the computed tomography (CT) findings of primary serous papillary carcinoma of the peritoneum. MATERIAL AND METHODS: The clinical data and imaging studies of 36 women aged 37-85 years with primary papillary serous carcinoma of the peritoneum were retrospectively evaluated. Twenty-seven patients presented with general abdominal complaints; all had elevated levels of CA-125. Thirty-two women were post-menopausal, four had had bilateral salpingo-oophorectomy. RESULTS: The most common findings on pre-operative abdominal CT, performed in 30 patients, were a variable amount of ascites (n = 29), omental involvement (n = 28), irregular parietal peritoneum thickening (n = 22) and mural thickening of the sigmoid colon (n = 10). Thoracic findings included enlarged cardiophrenic nodes (n = 15) and pleural effusion (n = 11). Six patients had unilateral or bilateral adnexal masses of soft tissue density, which proved to be surface serous papillary carcinoma. CONCLUSION: Diffuse peritoneal disease on CT in patients with normal-sized ovaries or following bilateral salpingo-oophorectomy, with elevated level of serum CA-125, but without an identifiable primary tumour, should suggest the diagnosis of primary serous papillary carcinoma of the peritoneum. Associated adnexal masses or focal bowel wall thickening may be seen, representing surface involvement by this tumour.

Adult↗
PubMed2001

Prevalence of the juxtaphrenic peak after upper lobectomy.

OBJECTIVE: The purpose of this study was to determine the prevalence of the juxtaphrenic peak after upper lobectomy in a large number of consecutive patients. MATERIALS AND METHODS: Available chest radiographs of 172 of 199 sequential patients who had undergone upper lobectomy in a university hospital were evaluated for the presence of a juxtaphrenic peak. The study included 98 cases with right upper lobectomy and 74 with left upper lobectomy. Radiographs were grouped in three postoperative periods: period I, within 7 days after lobectomy (n = 142); period II, between 8 and 30 days (n = 113); and period III, 31 days or more after lobectomy (n = 101). Four experienced radiologists in consensus determined the prevalence of the "juxtaphrenic peak sign," in relation to age, sex, side of lobectomy, positioning (erect or supine), presence of juxtadiaphragmatic abnormalities, and time interval since surgery. RESULTS: The prevalence of the juxtaphrenic peak sign gradually increased from 40.6% in period I to 71.9% in period III after right upper lobectomy (p < 0.01), and from 19% to 47.7%, respectively, after left upper lobectomy (p < 0.01). Its overall prevalence was significantly higher after right upper lobectomy (58.2%) than after left upper lobectomy (40.5%) (p = 0.02), and on erect chest films (51.4%) than on supine ones (28.9%). CONCLUSION: The prevalence of the juxtaphrenic peak sign increases gradually during the weeks following lobectomy. It is more frequent on erect films and after right upper lobectomy. The juxtaphrenic peak may serve as an additional useful radiologic sign suggesting upper lobectomy.

Adolescent↗
PubMed2001

Abdominal CT findings in nephropathic amyloidosis of familial Mediterranean fever.

To evaluate the abdominal CT features of reactive amyloidosis, abdominal CT scans of 20 patients with amyloidosis of familial Mediterranean fever (FMF) were reviewed and compared with abdominal CT scans of 2 control groups: 22 patients with chronic renal failure (CRF) due to non-amyloidotic kidney diseases and 40 patients with normal kidney function. The kidney size of patients with amyloidosis of FMF were found to vary during the course of the disease from normal or slightly larger than normal at the proteinuric phase, to smaller than normal and comparable to kidney size in CRF, at the uremic stage. Compared to kidney disease of other causes, more patients with FMF-amyloidosis had dense kidneys with coarse parenchymal calcification and calcification in other abdominal organs. Patients with FMF-amyloidosis had fewer aortic calcifications than patients with non-amyloidotic kidney disease. These findings suggest that kidney disease of reactive amyloidosis may have abdominal CT findings distinguishing it from other types of kidney diseases.

Abdomen↗
PubMed2001

Computerized tomography findings of abdominal tuberculosis: report of 19 cases.

BACKGROUND: Abdominal tuberculosis usually presents with general symptoms and obscure abdominal complaints for which computerized tomography is often the first imaging study. OBJECTIVE: To evaluate the CT findings of abdominal tuberculosis. METHODS: The CT scans of 19 patients (10 men and 9 women aged 20-85 years) with proven abdominal tuberculosis were retrospectively reviewed to define the location and extent of the disease. The patients were referred for the study mainly with general systemic symptoms. Additional abdominal complaints were present in four, including acute abdomen in one. Two had symptoms deriving from the urinary tract. Nine patients had recently arrived from high prevalence countries; five of them and two others were positive for human immunodeficiency virus. Three patients had a family history of tuberculosis; one had previously been treated for tuberculosis and four others had an underlying chronic disease. The diagnosis of tuberculosis was established by standard microbiological and histological techniques. RESULTS: We divided the disease manifestations into intraperitoneal (n = 13) and genitourinary involvement (n = 6). Peritoneal tuberculosis was fairly common, characterized by ascites, omental and mesenteric infiltration, and smooth thickening of the parietal peritoneum. One oncology patient had a false positive Tc-99m CEA isotope scanning, suggesting tumor recurrence. Genitourinary disease manifested mainly as hydronephrosis and calcifications. Three patients had pulmonary tuberculosis as well. CONCLUSION: The CT findings of abdominal tuberculosis may mimic various diseases, mainly diffuse peritoneal malignancy. We emphasize the need to consider tuberculosis in the differential diagnosis in patients with obscure abdominal symptoms, especially with multi-organ involvement. A high degree of clinical suspicion and familiarity with the abdominal CT manifestations allow early diagnosis of this treatable disease.

Adult↗
PubMed2000

B-cell-receptor-dependent positive and negative selection in immature B cells.

This review touches on only a small part of the complex biology of B cells, but serves to illustrate the point that the antigen receptor is the most important of many cell-surface receptors affecting cell-fate decisions. Receptor expression is necessary, but not sufficient, for cell survival. It is also essential that a B cell's antigen-receptor specificity be appropriate for its environment. The need to balance reactivity with self tolerance has resulted in an intricate feedback control (affected by both the recombinase and cell survival) that regulates independent selection events at the level of the receptor and the cell.

Animals↗
PubMed2000

CT findings in ten patients with failed renal allografts: comparison with findings in functional grafts.

Our aim is to report the computed tomography (CT) features of the long-term failed renal allograft. Ten patients with failed renal transplants in whom the graft was left in situ underwent CT for various unrelated indications. The majority of the failed grafts showed marked shrinkage and coarse punctate diffuse parenchymal calcifications. Small cysts were seen in four grafts. A long-term failed renal transplant appeared on CT as a small rounded soft tissue mass. The graft was almost always heavily calcified. Lack of awareness of the nature of such a mass may mislead the radiologist in interpreting it as a space-occupying lesion.

Adult↗
PubMed2000

B-cell antigen receptor competence regulates B-lymphocyte selection and survival.

Experimental evidence contradicts the simplistic view that during development all B cells expressing non autoreactive antigen receptors on the cell surface are selected into the mature B-cell pool. While allelic exclusion, clonal selection and affinity maturation continue to define the mainstream notions of B-cell development and selection, new evidence is redefining our understanding of these processes. Receptor editing replaces functional B-cell receptors by secondary immunoglobulin gene rearrangements, a process that can play roles in both immune tolerance and immune response. In addition, editing can rescue cells that would otherwise fail positive selection. We focus here on our studies indicating that the functional competence of the B-cell antigen receptor complex plays a central role in the fate of developing B cells and their antigen receptor genes.

Animals↗
PubMed1999

Influence of the high density lipoprotein receptor SR-BI on reproductive and cardiovascular pathophysiology.

The high density lipoprotein (HDL) receptor SR-BI (scavenger receptor class B type I) mediates the selective uptake of plasma HDL cholesterol by the liver and steroidogenic tissues. As a consequence, SR-BI can influence plasma HDL cholesterol levels, HDL structure, biliary cholesterol concentrations, and the uptake, storage, and utilization of cholesterol by steroid hormone-producing cells. Here we used homozygous null SR-BI knockout mice to show that SR-BI is required for maintaining normal biliary cholesterol levels, oocyte development, and female fertility. We also used SR-BI/apolipoprotein E double homozygous knockout mice to show that SR-BI can protect against early-onset atherosclerosis. Although the mechanisms underlying the effects of SR-BI loss on reproduction and atherosclerosis have not been established, potential causes include changes in (i) plasma lipoprotein levels and/or structure, (ii) cholesterol flux into or out of peripheral tissues (ovary, aortic wall), and (iii) reverse cholesterol transport, as indicated by the significant reduction of gallbladder bile cholesterol levels in SR-BI and SR-BI/apolipoprotein E double knockout mice relative to controls. If SR-BI has similar activities in humans, it may become an attractive target for therapeutic intervention in a variety of diseases.

Animals↗
PubMed1999

Peripheral blood allogeneic microchimerism in lung and cardiac allograft recipients.

We have been investigating two parameters, donor antigen-specific hyporeactivity and peripheral blood allogeneic microchimerism, to determine whether these parameters will predict a chronic rejection-free state and which recipients may be candidates for steroid withdrawal. We have identified donor antigen-specific hyporeactivity for 33% (16/48) of lung and 23% (11/47) of heart recipients. For both organ groups, the hyporeactive subgroup experienced a lower incidence of chronic rejection. The probability of donor antigen-specific hyporeactivity predicting a chronic rejection-free state is 100% for lung and 91% for heart recipients. We have identified peripheral blood allogeneic microchimerism for 77% (20/26) of lung and 36% (9/25) of heart recipients tested at 12-18 months posttransplant. Donor antigen-specific hyporeactivity correlates with a critical level of donor cells in lung recipients; the probability of high peripheral blood allogeneic microchimerism levels predicting a chronic rejection-free state in lung recipients is 100%. The results in heart recipients are not as clear with a short-, but not long-term, trend of higher chimerism levels correlating with the development of donor antigen-specific hyporeactivity. These results illustrate the usefulness of immmune parameters to predict long-term graft outcome in an organ-specific manner.

Bronchiolitis Obliterans↗
PubMed1999

Bezoars in the stomach and small bowel--CT appearance.

AIM: The aim of this study was to present the computed tomography (CT) appearance of trichobezoars, phytobezoars and other unusual ingested material. MATERIALS AND METHODS: Seven patients diagnosed on CT with bezoars in the stomach or small intestine were reviewed with special attention on the characteristics of the intraluminal mass and the presence of proximal dilatation. RESULTS: There were six women and one man aged 14-81 years. CT was performed because of abdominal pain and a palpable abdominal mass. In none of the cases was the diagnosis suspected clinically. Four patients had a trichobezoar occupying the entire lumen of the stomach. It appeared as a concentric inhomogeneous mass with entrapped air, surrounded by contrast material. In the other three patients the bezoar was confined to the small intestine and was composed respectively of vegetable fibres, ingested toilet paper and an olive stone. The first two had a mottled appearance whereas the last one was small, spherical and well defined. Variable proximal dilatation of the small bowel was present in all three. CONCLUSION: With the increased use of CT in the evaluation of patients with non-specific abdominal pain, it is important to recognize the CT appearance of bezoars, as this diagnosis is often not suspected clinically.

Adolescent↗
PubMed1998

V(D)J recombinase induction in splenic B lymphocytes is inhibited by antigen-receptor signalling.

In lymphocytes, DNA recombinations that generate the antigen-receptor genes can sometimes be reinduced in receptor-bearing cells in a process called receptor editing, which modifies the specificity of the receptor for antigen. In immature B lymphocytes, B-cell antigen receptor (BCR) signalling stimulates immune tolerance by receptor editing. More mature splenic B cells can also be induced to undergo V(D)J recombination, which generates diversity in the immune system, either by immunization with foreign proteins or by stimulation in vitro with interleukin-4 and lipopolysaccharides. Here we show that immune tolerance is unlikely to induce V(D)J recombination in mature B cells, because BCR ligation actively inhibits V(D)J recombination induced by interleukin-4 and lipopolysaccharide. Furthermore, immunization of immunoglobulin transgenic mice with ligands of varying avidities for the BCR showed that low-avidity antigen could induce strong V(D)J recombination, whereas non-binding or high-avidity ligands could not. These data suggest that V(D)J recombination induced during the immune response modifies the antigen receptors of B cells with weak, but not strong, reactivity to antigen, potentially rescuing cells with improved receptor affinity and promoting their contribution to the immune response. Thus BCR signalling regulates V(D)J recombination in both tolerance and immunity, but in strikingly different ways.

Animals↗
PubMed1998

Intussusception in adults: CT diagnosis.

PURPOSE: Intussusception in adults is nowadays usually diagnosed on computed tomography (CT), as CT is often the first modality for the investigation of prolonged abdominal pain from which these patients suffer. We wish to present the CT, clinical and pathological findings of 16 adult patients with intussusception seen over a 5-year period. MATERIALS AND METHODS: The abdominal scans of 16 patients with intussusception were reviewed. Special attention was directed to the location of the mass, its shape and fat content, possible underlying pathology and dilatation of the bowel proximally. The findings were correlated with clinical and pathological data. RESULTS: Eight men and eight women, aged 34-81 years, were studied. The most frequent indication for CT was prolonged abdominal pain. CT findings included an inhomogeneous soft tissue mass, target or sausage-shaped, depending on the angle of the CT beam vs. the intussusception, with a fatty component in 14 of the 16. Intussusception was enteroenteric (six), ileocolic (three), or colocolic (seven). Complete small bowel obstruction was present only in one case and some bowel dilatation in three. The underlying pathology could be diagnosed on CT in only two cases of lipoma. Nine patients had an underlying malignant process, eight of them unsuspected. Of the other five, two had coeliac disease, two were classified as idiopathic and one had a necrotic polyp of undetermined pathology. CONCLUSION: Intussusception on CT presented a characteristic mass lesion containing fat stripes in almost all patients. Obstruction was rarely seen. Malignant lesions were the most common cause and therefore early diagnosis and prompt intervention are essential.

Abdominal Pain↗
PubMed1998

Promoting adherence to an electronic home spirometry research program after lung transplantation.

Adherence with any long-term treatment or research protocol is a challenge; this has been found to be the case with lung transplant recipients participating in an electronic home spirometry research program. Because the purpose of the current study is to develop a system for detecting early infection and rejection in lung transplant recipients, regular transmission of data by subjects to the research data center is imperative to the success of the study. Various adherence-promoting strategies have been developed by the research team to increase subject adherence with the program. An increased adherence rate has been reported after implementation of these various strategies, yet work remains to promote continually regular participation in the program by all subjects. It remains a challenge for the research team to devise creative and effective strategies for increasing adherence to regular spirometer use to provide data to develop a computerized system for detecting early infection and rejection of transplanted lung tissue.

Algorithms↗
PubMed1998

Receptor editing and commitment in B lymphocytes.

B cells that fail to pass a developmental checkpoint, either as immature or mature B cells, can be rescued by creating a new B cell antigen receptor through nested secondary immunoglobulin gene rearrangements, a process termed receptor editing. Tolerance-mediated receptor editing occurs in self-reactive immature bone marrow B cells, while peripheral receptor editing probably occurs in low-affinity B cells competing for antigen and for survival signals within the germinal center response.

Animals↗
PubMed1997

BCR ligation induces receptor editing in IgM+IgD- bone marrow B cells in vitro.

The ability of BCR cross-linking to stimulate receptor editing was analyzed in vitro using bone marrow B cells from immunoglobulin (Ig) transgenic (Tg) and non-Tg mice. In cultured Ig-Tg cells, BCR ligation induced receptor editing as measured by up-regulation of RAG gene expression, light chain gene DNA rearrangements, and expression of lambda-light chain protein in cells that previously expressed kappa. In the culture conditions used, BCR ligation induced light chain rearrangements in most immature IgM+IgD- bone marrow B cells in the absence of significant cell death or cell growth. Receptor editing in non-Tg B cells was also documented in cultures treated with anti-immunoglobulin. These results provide direct evidence for the ability of BCR ligation to stimulate immunoglobulin light chain gene rearrangements in immature B cells.

Animals↗