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M M Maher

Publications and source records attributed to M M Maher.

At least 19 recordsLinked to original sources
PubMed2003

State-of-the-art imaging of pancreatic neoplasms.

Pancreatic imaging with multidetector CT allows multiphase acquisition of thin slices in a single breath-hold and is especially valuable in obtaining isotropic three-dimensional reformations that improves our ability to provide accurate pre-operative vascular mapping. Advanced MR technology allows faster imaging of pancreas, thus facilitating MR cholangiopancreatography. Use of tissue-specific MR contrast agents, endoscopic ultrasound and PET in pancreatic imaging has evolved considerably. This review article discusses the role of CT, MR, endoscopic ultrasound and PET imaging in pancreas.

Adenocarcinoma↗
PubMed2002

Predictive value of benign percutaneous adrenal biopsies in oncology patients.

PURPOSE: Percutaneous CT guided biopsy is accepted as a safe procedure for the diagnosis of indeterminate adrenal masses in oncologic patients. The purpose of this study was to evaluate the accuracy of a 'negative for tumour' adrenal biopsy in the oncologic patient population by assessing subsequent outcome including clinical course, size and imaging characteristics of the adrenal lesions on follow-up imaging studies and pathological findings at re-biopsy or following adrenal mass resection. MATERIALS AND METHODS: Retrospective analysis of 225 oncological patients (FM, 128;87; age range 33-87 years, mean age 66 years) who had undergone CT guided biopsies of an adrenal mass over a 5-year period was performed. Those patients with a report consistent with 'negative for malignancy' were evaluated by reviewing the medical records for patient demographics, primary malignancy, histology of adrenal tumour, subsequent surgical interventions, repeat adrenal biopsy under image guidance, by open surgery or at autopsy, subsequent abdominal imaging in which the adrenal gland was imaged, and long-term outcome including hospital admissions, or death. RESULTS: Of the 225 CT-guided adrenal biopsies performed, 41 (18%) were negative for neoplasm. The primary neoplasm in these 41 patients included lung cancer (n=32), breast (n=5), renal cell carcinoma (n=2), bladder (n=1), and prostate (n=1). The size of the adrenal lesions ranged from 2.8-5 cm. Of the 41 biopsies, which were negative for tumour; 10 were identified as adenomas and the rest showed benign adrenal cortical cells or hyperplasia on cytopathology and histopathology. Repeat biopsies were obtained in 13/41 (31%) patients; whereas 2/41 (5%) had their adrenal gland analyzed on post mortem examination. None of these 15 repeat evaluations yielded tumour. CONCLUSION: In oncological patients, pathological analysis of tissue samples obtained by CT-guided percutaneous biopsy, suggesting benign aetiology, is reliable and predicts a benign course on long-term follow-up. A negative or benign pathology result for a CT guided percutaneous adrenal biopsy can be regarded as a true negative evaluation in oncological patients with no necessity to repeat the biopsy.

Adenoma↗
PubMed2001

Growth and survival of E. coli O157:H7 during the manufacture and ripening of a smear-ripened cheese produced from raw milk.

AIMS: The behaviour of Escherichia coli O157:H7 was studied during the manufacture and ripening of a smear-ripened cheese produced from raw milk. METHODS AND RESULTS: Cheese was manufactured on a laboratory scale using milk (20 l) inoculated with E. coli O157:H7, and enumeration was carried out using CT-SMAC. From an initial level of 1.52 +/- 0.03 log cfu ml-1 in the milk (34 +/- 2 cfu ml-1), the numbers increased to 3.4 +/- 0.05 log cfu g-1 in the cheese at day 1. During ripening, the numbers decreased to <1 cfu g-1 and <10 cfu g-1 in the rind and core, respectively, after 21 days, although viable cells were detected by enrichment after 90 days. The presence of E. coli O157:H7 in the cheese was confirmed by latex agglutination and by multiplex PCR. CONCLUSION: The results indicate that the manufacturing procedure encouraged substantial growth of E. coli O157:H7 to levels that permitted survival during ripening and extended storage. SIGNIFICANCE AND IMPACT OF THE STUDY: The presence of low numbers of E. coli O157:H7 in milk, destined for raw milk cheese manufacture, could constitute a threat to the consumer.

Animals↗
PubMed2001

Imaging of primary non-Hodgkin's lymphoma of the liver.

AIM: To describe the radiological findings in primary liver lymphoma, which is a rare entity, presenting usually as a localized liver mass. MATERIALS AND METHODS: We reviewed retrospectively the imaging findings at presentation, of patients in whom a diagnosis of primary liver lymphoma was finally made histologically. The study period covered a 10-year period between January 1990 and December 1999. There were seven patients, all men, with a mean age of 49.6 years. Each patient presented with hepatobiliary disease without peripheral adenopathy. Imaging prior to diagnosis included ultrasonography (seven patients), computed tomography (seven patients) and magnetic resonance imaging (MRI) (two patients). Appearances during and after aggressive chemotherapy were reviewed. RESULTS: Imaging appearances were of either single or multiple liver lesions simulating liver metastases. On ultrasound all foci of primary hepatic lymphoma (PHL) were hypoechoic relative to normal liver. Computed tomography (CT) showed hypoattenuating lesions in all cases, and two cases showed rim enhancement following contrast administration. The MRI appearances were variable, and no pathognomonic feature of PHL was identified, so that histology was required in all patients to establish the diagnosis. CONCLUSIONS: This paper demonstrates the spectrum of findings encountered on various imaging modalities in PHL. We conclude that although PHL is a rare condition, it should always be considered in the differential diagnosis of liver metastases when no primary tumour is apparent.

Adult↗
PubMed2000

Giant distal humeral geode.

We describe the imaging features of a giant geode of the distal humerus in a patient with rheumatoid arthritis, which presented initially as a pathological fracture. The value of magnetic resonance imaging in establishing this diagnosis is emphasized.

Arthritis, Rheumatoid↗
PubMed2000

Spinal dysraphism at MR urography: initial experience.

PURPOSE: To prospectively evaluate the role of magnetic resonance (MR) urography in the radiologic assessment of patients with spinal dysraphism. MATERIALS AND METHODS: Fourteen patients with spinal dysraphism were referred for MR urography with half-Fourier rapid acquisition with relaxation enhancement (RARE) (repetition time msec/echo time msec = 11.9/95) and RARE (2,800/1,100) sequences on a 1.5-T MR machine. Six patients did not tolerate MR urography owing to claustrophobia (n = 4) or flexion deformities (n = 2), giving a final success rate of 57% (eight patients). Two patients had a single kidney (one after nephrectomy, one with a crossed-fused ectopic kidney). Images were jointly assessed by two radiologists and compared with excretory urographic studies. The signal intensity ratio and contrast-to-noise ratio were also calculated. RESULTS: Visualization of the kidneys, pelvicaliceal system, and ureters was better with half-Fourier RARE than with RARE imaging, whereas visualization of the bladder was comparable with both sequences. The mean signal intensity ratios for half-Fourier RARE and RARE sequences, respectively, were 16.2 +/- 3.65 and 19.2 +/- 3.65 (P =. 58, factorial analysis of variance model), whereas the mean contrast-to-noise ratios were 55.4 +/- 5.16 and 47.8 +/- 5.16 (P =. 34). Cortical scarring was depicted more clearly at MR urography than at excretory urography, whereas a renal calculus seen at excretory urography was not detected at MR urography. CONCLUSION: MR urography was feasible in 57% of patients with spinal dysraphism and is a safe, accurate method of evaluating the upper urinary tract.

Adolescent↗
PubMed2000

The beneficial role of transvaginal ultrasound in the preoperative characterisation of dermoid cysts of the ovary.

The advent of transvaginal sonography has improved the ability of radiologists to visualise both ovaries and has facilitated the preoperative characterisation of many of these lesions. We describe the beneficial role of transvaginal sonography in the accurate preoperative characterisation of dermoid cysts of the ovary in two patients and describe the characteristic features of ovarian dermoid cysts.

Adult↗
PubMed1998

Histopathologic changes seen in esophagectomy specimens from the high-risk region of Linxian, China: potential clues to an etiologic exposure?

Esophageal cancer is one of the most fatal cancers worldwide and is characterized by great variation in rates among different populations. Linxian, a county in Henan Province, located in north-central China, has one of the highest rates of esophageal squamous cell carcinoma in the world. Most squamous cell carcinomas in low-risk populations are attributable to alcohol and tobacco consumption, but the causative agents in high-risk populations are less clear. The prevention and treatment of esophageal cancer in high-risk regions, such as Linxian, are limited by our inability to identify these agent(s). During a preliminary histological review, the authors noticed characteristic findings in the arteries, nerves, and lymph nodes of esophagectomy specimens from Linxian and wondered whether these findings might offer clues to the cause of squamous cell carcinoma (eg, polycyclic aromatic hydrocarbon exposure) in the Linxian population. The purpose of this study was to report these previously undescribed histopathologic changes and to compare their presence and severity with those found in esophageal squamous cell carcinomas and adenocarcinomas from a lower-risk population in the United States. Forty esophagectomies were reviewed, including 13 squamous cell carcinomas from Linxian and 21 squamous cell carcinomas and six adenocarcinomas from the United States. The presence and severity of arteriosclerosis and myxoid degeneration of nerves and the presence of anthracosis in periesophageal lymph nodes were recorded. The prevalence and severity of these findings in the three groups of esophagectomies were compared. The esophageal squamous cell carcinomas from Linxian, China, had a higher prevalence of arteriosclerotic vessels, nerves with myxoid degeneration, and anthracotic lymph nodes than the squamous cell carcinomas from the United States (Wilcoxon test, P < .04 for all comparisons). There were also significant differences in the prevalence of arteriosclerotic vessels and anthracotic lymph nodes between the esophageal squamous cell carcinomas from Linxian and the adenocarcinomas from the United States. Arteriosclerosis and the myxoid degeneration were significantly more severe in the esophageal squamous cell carcinomas from Linxian than in the esophageal squamous cell carcinomas or adenocarcinomas from the United States (Mantel trend test, P < .006 for all comparisons). Arteriosclerotic vessels, nerves with myxoid degeneration, and anthracotic lymph nodes can be seen in association with esophageal squamous cell carcinomas from the high-risk region of Linxian, China. These changes appear to be more prevalent and severe than those seen in association with esophageal squamous cell carcinomas or adenocarcinomas from a low-risk population in the United States. These characteristic changes may be causatively significant and may represent histological evidence of high-level environmental exposure to polycyclic aromatic hydrocarbons.

Adenocarcinoma↗
PubMed1997

The Na+/H+ exchange isoform NHE3 regulates basal canine ileal Na+ absorption in vivo.

BACKGROUND & AIMS: Three different Na+/H+ exchange isoforms have been localized in mammalian ileum: Na+/H+ exchange isoform 1 (NHE1) on the basolateral membrane and NHE2 and NHE3 on the brush border membrane. The aim of this study was to determine whether NHE3 is the predominant isoform serving basal ileal Na+ absorption. METHODS: Immunocytochemistry was performed on canine ileum with specific polyclonal antibodies. Absorption studies (n = 58) were performed in dogs with 25-cm ileal Thiry-Vella fistulas. In groups 1-4, luminal 5-(N,N-dimethyl)-amiloride (DMA) was administered at doses of 100 nmol/L, 5 mumol/L, and 0.7 mmol/L to inhibit NHE1, NHE2, and NHE3, respectively. In groups 5-8, 1 mmol/L phlorizin (PHLZ), 0.7 mmol/L DMA, and 1 mmol/L PHLZ plus 0.7 mmol/L DMA were administered intraluminally. RESULTS: NHE2 and NHE3 were present in the brush border of canine ileal villus epithelial cells. The highest concentration of DMA (0.7 mmol/L) caused a significant reduction (P < 0.05) in basal ileal water and sodium absorption. PHLZ and 0.7 mmol/L DMA each alone significantly reduced basal ileal absorption (P < 0.05), whereas PHLZ plus 0.7 mmol/L DMA had an additive effect. CONCLUSIONS: NHE3 seems to be the Na+/H+ exchange isoform involved in the modulation of basal ileal water and sodium absorption. Both Na+/H+ exchange mediated through NHE3 and Na(+)-glucose cotransport contribute to basal ileal water and sodium absorption.

Amiloride↗
PubMed1997

Pancreaticoduodenectomy for selected periampullary neuroendocrine tumors: fifty patients.

BACKGROUND: Most resectable pancreatic or peripancreatic neuroendocrine tumors are treated by enucleation or distal pancreatectomy. A minority of tumors may require pancreaticoduodenectomy for complete tumor excision because of their large size, location, or lymph node involvement. METHODS: This study reviews the management of 50 patients treated by pancreaticoduodenectomy for periampullary neuroendocrine tumors between 1962 and 1996 at a single institution. RESULTS: There were 30 men and 20 women with a mean age of 52 +/- 2 years. Functional tumors were resected in 17 patients: insulinoma, seven tumors; gastrinoma, eight tumors; vipoma, one tumor; and glucagonoma, one tumor. Tumors were classified as malignant in 29 patients and benign in 21. The median intraoperative blood loss was 800 ml, and the median number of units of blood transfused was zero. The postoperative length of stay was 20 +/- 2 days. Postoperative morbidity included 11 patients (24%) with a pancreatic fistula and four patients (8%) with a biliary fistula. There was one in-hospital death (2%), in 1967. The actuarial survival rates at 2, 5, and 7 years are 81%, 73%, and 65%, respectively. Patients with benign tumors had a significantly improved 5-year survival rate (94%) compared with those with malignant tumors (61%; p = 0.03). CONCLUSIONS: Selected patients with periampullary neuroendocrine tumors can be managed successfully by pancreaticoduodenectomy, with low mortality and acceptable morbidity rates.

Adult↗
PubMed1997

Risk factors and early detection of lung cancer in a cohort of Chinese tin miners.

PURPOSE: To examine risk factors and establish a biologic specimen and data bank for the study of early markers of lung cancer. METHODS: We designed a dynamic cohort using an ongoing lung cancer screening program among radon- and arsenic-exposed tin miners in Yunnan China. Through the first four years of the study, 8,346 miners aged 40 years and older with over 10 years of occupational exposure have been enrolled, risk factors have been assessed, annual sputum and chest radiographs have been obtained, and numerous biologic specimens have been collected. RESULTS: A total of 243 new lung cancer cases have been identified through 1995. Radon and arsenic exposures are the predominant risk factors, but lung cancer risk is also associated with chronic bronchitis and silicosis, as well as a number of exposure to tobacco smoke, including early age of first use, duration, and cumulative exposure. Tumor and sputum samples are being examined for early markers of lung cancer. CONCLUSION: A cohort of occupationally-exposed tin miners with an extensive biologic specimen repository has been successfully established to simultaneously study the etiology and early detection of lung cancer.

Adult↗
PubMed1997

Effects of strength or aerobic training on body composition, resting metabolic rate, and peak oxygen consumption in obese dieting subjects.

Given that resting metabolic rate (RMR) is related largely to the amount of fat-free mass (FFM), the hypothesis was that strength training, which stimulates muscle hypertrophy, would help preserve both FFM and RMR during dieting. In a randomized controlled intervention trial, moderately obese subjects (aged 19-48 y) were assigned to one of three groups: diet plus strength training, diet plus aerobic training, or diet only. Sixty-five subjects (25 men and 40 women) completed the study. They received a formula diet with an energy content of 70% of RMR or 5150 +/- 1070 kJ/d (x +/- SD) during the 8-wk intervention. They were seen weekly for individual nutritional counseling. Subjects in the two exercise groups, designed to be isoenergetic, trained three times per week under supervision. Those in the strength-training group performed progressive weight-resistance exercises for the upper and lower body. Those in the aerobic group performed alternate leg and arm cycling. After 8 wk, the mean amount of weight lost, 9.0 kg, did not differ significantly among groups. The strength-training group, however, lost significantly less FFM (P < 0.05) than the aerobic and diet-only groups. The strength-training group also showed significant increases (P < 0.05) in anthropometrically measured flexed arm muscle mass and grip strength. Mean RMR declined significantly, without differing among groups. Peak oxygen consumption increased the most for the aerobic group (P = 0.03). In conclusion, strength training significantly reduced the loss of FFM during dieting but did not prevent the decline in RMR.

Adult↗
PubMed1996

Role of brush border Na+/H+ exchange in canine ileal absorption.

Na+/H+ exchanger isoforms have been identified in mammalian intestinal enterocytes and cloned: NHE1 on the basolateral membrane regulating intracellular pH; and NHE2 and NHE3 on the brush border serving transcellular absorption in Na+. NHE1 and NHE2 are much more sensitive to inhibition by amiloride than NHE3, their in vitro IC50s for amiloride being 1 microM, 1 microM and 39 microM, respectively. This study tested the hypothesis that the brush border NHE3 isoform plays the predominant role in basal and meal-stimulated ileal absorption. Absorption studies (N = 72) were performed in dogs with 25-cm ileal Thiry-Vella fistulae. Six groups were studied over 4 hr. Perfusion with [14C]PEG and 140 mM Na+ was used to calculate absorption of water, ions, and glucose. Luminal amiloride was administered from the second to the fourth hours at doses of 20 microM in groups 3 and 4 to inhibit NHE1 and NHE2, and 1mM in groups 5 and 6 to also inhibit NHE3. A 480-kcal canine meal was ingested after the second hour in groups, 2, 4, and 6. Meal ingestion was followed by significant increases in water and electrolyte absorption. Amiloride (1 mM) caused significant reductions in basal and meal-stimulated ileal absorption, while the 20 microM dose had no effect on either. These data are consistent with the hypothesis that NHE3, but not NHE2, is involved in basal and meal-stimulated ileal water and Na+ absorption.

Amiloride↗
PubMed1996

Pancreas-sparing duodenectomy for infra-ampullary duodenal pathology.

BACKGROUND: Surgical management of distal duodenal pathology is challenging because of the duodenum's retroperitoneal location and its shared blood supply with the pancreas. For infra-ampullary pathology, surgical treatment may include local excision, pancreaticoduodenectomy, or pancreas-sparing duodenectomy (PSD). PATIENTS AND METHODS: We retrospectively reviewed the management of 24 patients with infra-ampullary duodenal pathology treated by PSD between 1985 and 1994 at The Johns Hopkins Hospital. RESULTS: There were 16 men and 8 women with a mean age of 51.2 +/- 4.4 years. The indications for elective PSD in 19 patients were neoplasms (n = 15), Crohn's disease (n = 2), and other (n = 2). Of the neoplasms, 13 were malignant (11 adenocarcinoma, 1 lymphoma, 1 liposarcoma) and 2 were being (1 villous adenoma, 1 benign stromal tumor). Five patients had PSD as an emergency procedure for penetrating trauma. The mean follow-up is 24.2 +/- 5.8 months (range 1 to 122). In the group undergoing elective PSD, the mean length of operation was 5.3 +/- 0.4 hours, and the estimated blood loss was 569 +/- 121 mL. In the entire series, there was 1 postoperative death from an anastomotic leak and 1 reexploration for anastomotic bleeding. Pancreas-sparing duodenectomy in patients with trauma or benign duodenal pathology resulted in a good outcome in all. In those 11 patients with duodenal adenocarcinoma, 7 have died, 2 have had recurrences, and 2 are disease free. Actuarial and disease-free, 2-year survival rates in the 11 patients with duodenal adenocarcinoma were 33% and 14%, respectively. CONCLUSIONS: Pancreas-sparing duodenectomy is a safe and effective treatment in patients with distal duodenal benign neoplasms or trauma, and PSD appears to have limited effectiveness for malignant distal duodenal pathology.

Ampulla of Vater↗
PubMed1995

Endogenous nitric oxide promotes ileal absorption.

BACKGROUND/AIMS: Nitric oxide (NO) is generated in vascular endothelium and enteric neural plexuses from L-arginine by the action of nitric oxide synthase (NOS). This study tested the hypothesis that NO is a modulator of ileal water and ion transport. METHODS: NADPH diaphorase staining was performed on fixed frozen sections of canine ileum. Absorption studies (n = 80) were performed in five dogs with 25-cm ileal Thiry-Vella fistulas (TVF). Perfusion with [14C]PEG was used to calculate absorption of water, ions, and glucose from the TVF. Experiments comprised three 1-hr periods: basal, drug infusion, and recovery. Drugs infused luminally at 5 x 10(-4) mol/liter included L-ARG (NOS substrate), L-NAME (NOS inhibitor), L-ARG/L-NAME combination, D-ARG (inactive enantiomer of L-ARG), L-LYS (basic amino acid control for L-ARG), and SNAP (NO donor). RESULTS: NADPH diaphorase staining indicated NOS activity in the ileal mucosa and submucosa. L-ARG and SNAP caused significant increases in water and ion absorption, whereas L-NAME caused significant decreases. The prosecretory effect of L-NAME was completely reversed by synchronous L-ARG. D-ARG and L-LYS had no significant effects. No infused agent influenced [14C]PEG recovery. CONCLUSIONS: Inhibition of endogenous NO synthesis by L-NAME causes a prosecretory response for water and ions, which can be reversed by the administration of NOS substrate L-ARG. These results are consistent with the hypothesis that endogenous NO maintains a proabsorptive influence on water and ion transport in the ileum.

Animals↗