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J P Jenkins

Publications and source records attributed to J P Jenkins.

At least 19 recordsLinked to original sources
PubMed1998

Stage 0 mucinous adenocarcinoma in situ of the urachus.

Adenocarcinomas of the urinary bladder are rare (1-5% of bladder tumours) and of notoriously poor prognosis. About one third of such tumours arise in urachal remnants related to the bladder. This is believed to be the first report of in situ change in the urachal remnant. The patient presented with mucusuria and computed tomography showed a typical urachal cyst. After excision the cyst was found to contain mucinous adenomatous epithelium but without invasion of the basal lamina. Pathological stage is the best prognostic indicator in urachal tumours. Prompt investigation and management of mucusuria may allow the diagnosis of urachal tumours in this preinvasive stage.

Adenocarcinoma, Mucinous↗
PubMed1998

Bicarbonate/lactate- and bicarbonate-buffered peritoneal dialysis fluids improve ex vivo peritoneal macrophage TNFalpha secretion.

Peritoneal macrophage (PMO) function was examined ex vivo after their in vivo exposure to either acidic, lactate-buffered solutions (PD4; 40 mM lactate, pH 5.2), bicarbonate/lactate-buffered solution (TBL; 25 mM/15 mM bicarbonate/lactate, pH 7.3), or bicarbonate-buffered solution (TB; 38 mM bicarbonate, pH 7.3), containing either 1.36 or 3.86% glucose. Initial experiments demonstrated that tumor necrosis factor-alpha (TNFalpha) release (assessed by TNF-direct immunoassay [DIA]) from PMO isolated from the peritoneal cavities of patients exposed to conventional fluid (PD4 1.36% glucose) was lowest after 30 min of intraperitoneal dwell (3591+/-1200 versus 28,946+/-9359 for 240-min dwell [pg/ml], n=5, P < 0.05). Five patients were exposed on 3 successive days to PD4, TBL, and TB for 30-min acute dwells containing 1.36% glucose in the first week and 3.86% glucose during the second. PMO TNFalpha release was assessed after ex vitro exposure to lipopolysaccharide (LPS). Exposure of PMO to TBL or TB (1.36% glucose) resulted in a significant increase in the generation of TNFalpha (pg/2 X 10(6) PMO) compared with PD4. TBL: 68,659+/-35,633, TB: 53,682+/-26,536 versus PD4 17,107+/-8996 (LPS 1.0 ng/ml, n=5 patients, P=0.043 versus PD4 for both). PMO that were recovered from PD4 and TB dwells (3.86% glucose) showed no significant difference in TNFalpha secretion (21,661+/-6934 and 23,923+/-9147, respectively). In contrast, exposure to TBL resulted in a significant increase (41,846+/-11,471) compared with PD4 (LPS 1.0 ng/ml, n=5 patients, P=0.043). These data demonstrate enhanced PMO function after in vivo exposure to bicarbonate- and bicarbonate/lactate-buffered solutions. This response was sustained in TBL alone at the highest glucose concentrations. These results suggest that the newer solutions, and particularly bicarbonate/lactate, might improve host defense status in peritoneal dialysis patients.

Aged↗
PubMed1997

The influence of chemical shift artifact on magnetic resonance imaging of the ligamentum flavum at 0.5 tesla.

STUDY DESIGN: Retrospective clinical magnetic resonance imaging study and prospective magnetic resonance imaging volunteer study of the appearance of the ligamentum flavum. OBJECTIVE: To demonstrate the effect of chemical shift artifact on the apparent thickness of the ligamentum flavum on axial magnetic resonance images. SUMMARY OF BACKGROUND DATA: The ligamentum flavum is a symmetric structure clearly seen on magnetic resonance images. Apparent unilateral thickening may be interpreted as indicating a pathologic process, and the influence of chemical shift artifact on the apparent thickness of the ligamentum flavum has not been emphasized. METHODS: Ligamenta flava thicknesses were measured from axial T1-weighted gradient echo magnetic resonance scans of 12 consecutive patients and various axial sequences in seven volunteers. RESULTS: The ligamentum flavum appeared consistently thicker on the lower side of the readout gradient field. This chemical shift effect could be manipulated by swapping phase and frequency or patient orientation in the magnet. CONCLUSIONS: Caution should be applied in attributing apparent asymmetry of the ligamenta flava to disease; the influence of chemical shift artifact should be considered.

Adolescent↗
PubMed1997

MRI of the brain and craniocervical junction in Morquio's disease.

We reviewed MRI of the brain and cervical spine in 11 patients with Morquio's disease. No abnormality was seen in the brain. The odontoid peg was abnormal in all patients, with varying degrees of cord compression due to an anterior soft tissue mass and indentation by the posterior arch of the atlas. The degree of cord compression was more marked than suggested by the symptoms and signs. We recommend MRI of the cervical spine in children with Morquio's disease before the development of neurological symptoms, to optimise the timing and type of surgical intervention.

Adolescent↗
PubMed1996

Magnetic resonance imaging in macromelia and macrodactyly.

We report five cases presenting with soft tissue and bone overgrowth that demonstrate the ability of MRI to establish a diagnosis in the absence of specific clinical features. Disorders included macrodystrophia lipomatosa, angiolipomatosis, Klippel-Trenaunay-Weber syndrome, blue rubber bleb naevus syndrome and one case of segmental limited hypertrophy. The MRI appearances, and other radiological features of these conditions are discussed. MRI is recommended in all cases of macrodystrophy when the clinical features and plain film findings are indeterminate.

Adult↗
PubMed1995

Herniated intervertebral disc-associated periradicular fibrosis and vascular abnormalities occur without inflammatory cell infiltration.

STUDY DESIGN: Prospective histologic comparison of perineural tissues from patients requiring decompression surgery for herniated intervertebral disc with those from cadaveric controls. OBJECTIVES: To examine the significance of herniated intervertebral-disc-associated perineural vascular and fibrotic abnormalities with respect to back pain symptom generation. SUMMARY OF BACKGROUND DATA: Previous cadaveric studies have demonstrated perineural vascular congestion, dilatation, and thrombosis and perineural and intraneural fibrosis occurring in association with herniated intervertebral disc. It was suggested that these neural abnormalities were the result of ischemia, due to venous outflow obstruction, and also represented a possible cause of ongoing back pain symptoms. Criticisms of such a conclusion arose, however, because the possibility could not be excluded that these abnormalities were the result of postmortem artifact. METHODS: Histologic and immunohistochemical comparison of discal and peridiscal tissues removed from 11 patients with radiographically proven herniated intervertebral disc requiring decompressive surgery and from 6 fresh cadavers without history of back pain in life. RESULTS: Histology and immunohistochemistry of perineural and extraneural tissues from patients revealed vascular congestion, neovascularization, and endothelial abnormalities including luminal platelet adhesion, in association with reductions in von Willebrand factor levels, together with perivascular and perineural fibrosis. Elevated fibrogenic cytokine concentrations were also detected in patients' tissues. These changes occurred without evidence of inflammation and were absent in cadaveric control tissues. CONCLUSIONS: The vascular abnormalities detected in patients may represent an important etiopathologic factor predisposing to intraneural and perineural fibrosis, and hence to chronic pain symptoms, after disc herniation. It seems important to preserve the perineural microcirculation following disc herniation.

Adult↗
PubMed1995

MR imaging appearances of cervical epidural abscess.

Epidural abscess of the cervical spine is an uncommon disorder. The presentation is often non-specific and the diagnosis unsuspected. Magnetic resonance (MR) imaging is now considered the imaging investigation of choice. We report six patients with cervical epidural abscess diagnosed on MR imaging. The MR imaging showed the abscess to have a variable appearance and enhancement characteristics. Follow-up MR examinations confirmed resolution of the abscess and, in five cases, allowed conservative management.

Abscess↗
PubMed1995

Magnetic resonance imaging in phenylketonuria: reversal of cerebral white matter change.

OBJECTIVES: To investigate the extent to which the abnormalities in cerebral white matter in adolescents and adults with phenylketonuria (PKU) are reversible. METHOD: Magnetic resonance imaging (MRI) of the brain was repeated in 41 patients with PKU (age range, 14 to 49 years) after an interval (median, 9 months; range, 3 to 12 months) of dietary intervention. Scans were scored according to the extent of the white matter involvement. After an initial MRI, five patients returned to a strict low-phenylalanine diet with amino acid supplement; 21 patients started a low-protein diet (1 gm/kg) with amino acids supplement; and 15 patients made no dietary alteration. RESULTS: Scans improved in all five patients who returned to a strict low-phenylalanine diet, in 5 of the 21 patients on the low-protein diet plus amino acid supplement, and in 4 of the 15 patients who made no dietary change. There was a significant association between change in the MRI findings and in the blood phenylalanine concentration (Pearson correlation: r = 0.55; p < 0.0002) and between change in the MRI and in the phenylalanine level at the time of the second scan (r = 0.58; p < 0.0001). Improvement was seen primarily in those in whom phenylalanine levels were reduced to less than 900 mumol/L. There was no obvious change in MRI score after 3 weeks of strict phenylalanine restriction for the two adults who underwent serial scanning. CONCLUSION: The MRI changes in PKU are at least partially reversible by lowering the blood phenylalanine concentration.

Adolescent↗
PubMed1994

Magnetic resonance imaging of the brain in phenylketonuria.

Abnormalities of magnetic resonance imaging (MRI) of the brain occur in some patients with phenylketonuria but the clinical importance of this finding is not clear. In order to determine the frequency and functional significance of changes on MRI we investigated 77 adolescent and adult patients with phenylketonuria. Patients aged 14-49 years and taking a restricted diet of 1 g/kg protein underwent clinical examination, IQ testing, neurophysiological investigation, and MRI of the brain. Patients aged between 10-14 years taking a low phenylalanine diet with amino acid supplements had MRI of the brain only. Biochemical control was assessed from: the lifetime blood phenylalanine determined from the mean blood concentration throughout life; the accumulated time for each patient that phenylalanine was < 120 mumol/L; the accumulated time for each patient that phenylalanine was > 1200 mumol/L); mean blood concentration in the first 4 years of life; and the mean blood phe concentration in the 5 years prior to imaging. MRI changes, compatible with a disturbance in the water content of white matter, were present in all but 1 patient. The severity of abnormality was most strongly associated with the blood phenylalanine concentration at the time of imaging. Clinical and neurophysiological abnormalities were less common and usually mild. 3 patients had prolonged central motor conduction time, 7 had prolonged visual evoked potentials, and 5 had impaired peripheral sensory nerve conduction. There was no significant association between the extent of MRI abnormalities and IQ, and the presence of neurophysiological, or clinical abnormalities. An abnormal brain scan in PKU may reflect present biochemical control rather than indicate significant neurological damage. As yet there is little evidence that in most patients with PKU these MRI changes are of clinical importance.

Adolescent↗
PubMed1992

Epicardial controlled-release verapamil prevents ventricular tachycardia episodes induced by acute ischemia in a canine model.

Sustained-release preparations composed of verapamil-polymeric controlled-release matrices were characterized in vitro and utilized as epicardial implants in dogs with ischemic ventricular arrhythmias. Anesthetized open-chest dogs were subjected to 5 hourly, 10-min complete occlusions of the left anterior descending coronary artery followed by reperfusion. A controlled-release matrix preparation (20% verapamil, 80% polyurethane), placed on the left ventricular epicardium prior to the third occlusion, resulted in successful inhibition of ventricular tachycardia (VT) during acute ischemia in a dose-dependent manner. The largest matrix size used, 300 mg (20% verapamil), provided a net systemic dose of 0.52 +/- 0.18 mg/kg over 140 min and significantly reduced VT episodes during acute ischemia (fifth occlusion) compared to untreated controls (0.16 +/- 0.04 vs. 1.01 +/- 0.35 episodes/min, respectively; t = 2.62, p = 0.01). In controls, by the fifth occlusion ventricular fibrillation (VF) occurred after 5.41 +/- 0.78 min in 89% of animals. However, after a 300-mg verapamil matrix was placed on the left ventricular ischemic zone, VF occurred in only 45% (chi-squared = 4.1, p = 0.04, vs. controls) of the animals after 7.87 +/- 0.92 min (fifth occlusion). Systemic venous plasma verapamil levels during the 2 h following the 300-mg matrix ischemic zone implantation ranged from 8.4-22.0 ng/ml, while simultaneous regional coronary venous levels were 125.0-387.0 ng/ml. Sonomicrometry studies of left ventricular wall thickening carried out with a series of 300-mg verapamil matrix cardiac implants did not demonstrate any significant myocardial dysfunction. It is concluded that controlled-release verapamil, administered directly to the heart, was effective for preventing VT and VF associated with acute coronary ischemia, and that this route of administration was not associated with any significant deterioration of cardiac function.

Animals↗
PubMed1991

Investigation of children with suspected spinal dysraphism by magnetic resonance imaging.

Findings on Magnetic Resonance Imaging (MRI) of 52 children with suspected spinal dysraphism have been reviewed. In 24, no significant spinal abnormality was demonstrated. Seven patients had scoliosis or vertebral segmentation anomalies without demonstrable abnormality of the underlying soft tissues and one had an isolated subcutaneous haemangioma. In 20 children with spinal dysraphism, a low tethered cord was the most frequent finding, occurring in 80%. Other manifestations included myelo- or meningocoele (60%), syringomyelia (30%), lipoma (25%), congenital tumour (20%), diastematomyelia (15%) and thickened filum terminale (5%). The relationship between the clinical reason for requesting MRI and the scan results are discussed.

Adolescent↗
PubMed1990

Musculoskeletal haemangiomas: comparison of MRI with CT.

MRI and CT findings were reviewed from 11 patients with musculoskeletal haemangiomas. With MRI, morphological characteristics and extent of haemangiomas were optimally demonstrated on T2-weighted spin echo scans. High-resolution contrast-enhanced CT provided equivalent information regarding lesional characteristics and extent for small, localized haemangiomas. In CT evaluation of the extent of large haemangiomas, the radiation dose, transaxial scan plane, amount of intravenous contrast medium required and the necessity for correct timing of post-contrast scans became limiting factors. For such lesions, particularly those extending into the trunk, MRI supplemented by a plain radiograph is the optimum method of evaluation.

Adolescent↗
PubMed1990

Magnetic resonance imaging of musculoaponeurotic fibromatosis.

Musculoaponeurotic fibromatosis can be mistaken for soft-tissue sarcoma both clinically and on X-ray computed tomography. Magnetic resonance imaging (MRI) in three patients with this condition enabled the correct diagnosis to be made prospectively in two. The appearance on MRI of a heterogeneous mass with well-defined, predominantly peripheral areas of very low signal intensity due to dense fibrous tissue and areas of medium to high signal intensity corresponding to a more cellular stroma should raise the the suspicion of musculoaponeurotic fibromatosis. Cellular areas within the tumour showed moderate enhancement after gadolinium diethylene triamine pentaacetic acid administration.

Adult↗
PubMed1990

Accuracy in staging carcinoma of the bladder by magnetic resonance imaging.

Thirty-four patients with a presumptive diagnosis of carcinoma of the bladder diagnosed at EUA and cystoscopy have been staged by MRI and the findings correlated with pathology in 15 patients and clinical follow-up, including repeat cystoscopy, in the remainder. MRI is accurate in identifying tumours confined to the bladder wall or extending beyond the wall to involve perivesical fat or adjacent organs. Whilst it is not possible to distinguish between T1, T2 or early T3a tumours they can be distinguished from advanced T3a lesions and this may affect management. MRI is superior to clinical staging, particularly in detecting lymphadenopathy and provides information for optimal radiotherapy planning. The problem of distinguishing between the effects of radiotherapy and suspected recurrent tumour is discussed.

Aged↗
PubMed1989

Diagnosis and assessment of mitral and aortic valve disease by cine-flow magnetic resonance imaging.

Seventy-six aortic and mitral valves, in 44 patients and 5 normal volunteers, were studied by Cine-Flow MRI (on a 0.26-T superconducting magnet system), utilizing compound oblique imaging planes and a Field Echo Even Rephasing sequence. All patients had had cardiac catheterization and echocardiography. All patients with valvular stenosis and aortic sclerosis (n = 45) showed complete signal loss distal to the respective valve. Length of signal loss distal to the aortic valve in those in whom it was measured (n = 15) allowed differentiation of aortic stenosis (n = 9) from sclerosis (n = 6). This also permitted grading of stenosis with highly significant correlation (T = 0.86; P less than 0.002) with pressure gradient measurement. In mitral stenosis (n = 12) calculation of the area of signal loss distal to the mitral valve as a percentage of left ventricular cross-sectional area showed a highly significant correlation (T = 0.77; P = 0.001) with pressure gradient measurement. Clinically significant valvular regurgitation was graded by size and duration of signal loss proximal to the value with concordance with angiocardiography. It is concluded that Cine-Flow MRI has a clinical role in the diagnosis and assessment of valvular heart disease.

Adult↗
PubMed1988

Gadolinium-DTPA as a contrast agent in magnetic resonance imaging of the brain.

One hundred patients with CT-proven intracranial disease have been studied by magnetic resonance imaging (MRI) before and after intravenous injection with Gadolinium-DTPA (Gd-DTPA), in order to assess the role and clinical efficacy of Gd-DTPA. T2-weighted spin echo sequences, although sensitive to the detection of intracranial disease, in general fail to differentiate macroscopic tumor from oedema. Following Gd-DTPA, T1-weighted spin echo sequences in primary tumours demonstrated a variable degree of contrast enhancement unrelated to histological type. Small tumours, especially acoustic neuromas and meningiomas in the posterior fossa, were rendered more conspicuous. Optimum time for scanning was between five and 25 min following injection for all lesions except those adjacent to normal enhancing structures such as nasal/sinus mucosa and pituitary gland when delayed scans up to 45 min were necessary. No differences were observed between the 0.1 and 0.2 mmol/kg Gd-DTPA concentrations used and no complications attributable to Gd-DTPA were detected. Clinical advantages of Gd-DTPA include shorter scan times, macroscopic tumour/oedema separation and improved detection of certain tumours, particularly acoustic neuromas.

Adolescent↗