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Biomedical subjects

G John

Publications and source records attributed to G John.

At least 73 records · Page 4Linked to original sources
PubMed1982

A controlled comparison of flupenthixol decanoate injections and oral amitriptyline in depressed out-patients.

Sixty-eight depressed out-patients were allocated to treatment with either oral amitriptyline (75-225 mg/day) or intramuscular flupenthixol decanoate (10-30 mg every 14 days) in flexible dosage for 12 weeks under double-blind procedures. Various observer- and self-rating scales were applied before and after 2, 4, 8 and 12 weeks of treatment. Twenty-four patients completed the course of amitriptyline and 20 the course of flupenthixol. All variables improved over time, but there were no significant differences between the two drugs. The Newcastle scores pre-treatment were not related to drug response suggesting that both drugs were similarly effective across a wide spectrum of depressive disorders. Patients on amitriptyline tended to complain of dry mouth; those on flupenthixol had a higher incidence of extrapyramidal signs, the majority receiving anti-parkinsonian drugs at some time during the treatment. Flupenthixol decanoate in low dose is a useful anti-depressant, but should be restricted to short courses of treatment, to patients refractory to other treatments, and to patients suspected of poor compliance.

Administration, Oral↗
PubMed1981

Transient osteosclerosis associated with sodium valproate.

A 15-year-old boy on sodium valproate presented with pain in the extremities which had not responded to aspirin. X-ray of the long bones showed increased density in the metaphyses. After discontinuation of the drug his symptoms and the X-ray abnormalities disappeared.

Adolescent↗
PubMed1979

Measurement of activity of 5-HT antagonists following oral administration in man: a comparison of methysergide and BW501.

1 Oral doses of BW501 and methysergide administered to healthy volunteers inhibited the ex vivo platelet aggregation response to 5-hydroxytryptamine (5-HT). 2 Two volunteers received 100 mg BW501 and two received 10 mg BW501 and aggregation response was measured immediately pre drug and at 1,3 and 24 h post drug. After 100 mg BW501 the response to 5-HT was completely inhibited at all times studied, after 10 BW501 a response too small to measure was apparent at 24 h only. 3 In two randomised crossover studies subjects received either 2 mg BW501 (nine subjects), 2 mg methysergide (six subjects) or no drug (nine subjects) and aggregation response to 5-HT was measured immediately pre drug and at 1, 2, 3, 5, 7, 24 h post drug. 4 Methysergide (2 mg) produced complete inhibition of aggregation for 24 h after dosing; following 2 mg BW501 the aggregation response was significantly lower than on the control occasion at 1 (P less than 0.01), 2 (P less than 0.01) and 3 (P less than 0.05) h post drug. The response was inhibited by rr%, 31% and 16% at these times respectively. 5 It is suggested that this technique provides a suitable method for demonstration of activity of 5-HT antagonists after oral dosing in man.

Administration, Oral↗
PubMedDate not supplied

Small bowel neoplastic disease: demonstration by MRI.

This study demonstrates the appearance of small bowel tumors on MR images. Sixteen patients with tumors involving small bowel were studied by MRI. All tumors were proven with histopathology. Eleven patients had primary tumors of the small bowel, which included the following: four carcinoid tumors, three adenocarcinomas, two lymphomas, one leiomyosarcoma, and one leiomyoma. Five patients had recurrent or metastatic disease to small bowel: two patients had colon cancer, one patient had pancreatic cancer, one patient had uterine leiomyosarcoma, and one patient had chloroma (leukemia). MR examination included breath-hold T1-weighted spoiled gradient echo (all patients), immediate postgadolinium-spoiled gradient echo (10 patients), and 2 to 4 minutes postgadolinium T1-weighted, fat-suppressed images (all patients). Tumor size, local extent, signal intensity, and enhancement features of tumor and adjacent tissue were determined. Tumor ranged in diameter from 1 to 9 cm (mean, 4.0 cm). Tumors had similar signal intensity to normal small bowel on precontrast images. Fourteen malignant tumors showed heterogeneous enhancement greater than adjacent bowel on gadolinium-enhanced images. Tumor local extent was best shown on precontrast-spoiled gradient-echo images and postgadolinium T1-weighted fat-suppressed images. Image quality was most consistent on breath-hold images. The results of this study show that small bowel tumors are demonstrable on MR images. Precontrast breath-hold T1-weighted spoiled gradient-echo images and gadolinium-enhanced fat suppressed images demonstrate tumor extent most reliably.

Adult↗
PubMedDate not supplied

Ampullary carcinoma: demonstration by current MR techniques.

The objective of this study was to demonstrate the appearance of ampullary carcinoma using current MR techniques, including fat suppression, gadolinium enhancement, and MR cholangiography. Nine patients with ampullary carcinoma were examined by MRI at 1.5 T. MR examinations included T1-weighted spoiled gradient echo, T1-weighted fat-suppressed, and immediate postgadolinium spoiled gradient echo images for all patients and MR cholangiography for three patients. The imaging features of ampullary carcinomas, including tumor size and morphology, signal intensity, and enhancement characteristics, were determined. Ampullary carcinomas shown on MR images ranged in size from 1.5 to 5.5 cm. Tumors were low in signal intensity on precontrast T1-weighted spoiled gradient echo and T1-weighted fat-suppressed images relative to normal pancreatic tissue and enhanced less than normal pancreas on immediate postgadolinium spoiled gradient echo images. Tumor conspicuity was greatest on immediate postgadolinium spoiled gradient echo images. MR cholangiography demonstrated high grade obstruction of the common bile duct and mild dilatation of the pancreatic duct at the level of the ampulla with abrupt termination of the ducts in two untreated patients and moderate dilatation of the common bile duct in one patient who had a biliary stent. Ampullary carcinomas can be demonstrated on MR images as small masses arising at the ampulla. Tumors are well defined on immediate postgadolinium spoiled gradient echo images.

Adenocarcinoma↗
PubMedDate not supplied

Renal cell cancer: incidence of hemorrhage on MR images in patients with chronic renal insufficiency.

This study describes the occurrence of hemorrhage in renal cancer in patients with chronic renal insufficiency as shown on MR images. Thirteen consecutive patients with chronic renal insufficiency who had histologically proven renal cancer and underwent MRI at 1.5 T were entered in the study. MR examinations included spoiled gradient echo (SGE) and T1-weighted fat-suppressed imaging pre- and postgadolinium administration. All renal cancers were well shown on MR images and were most clearly depicted on postgadolinium T1-weighted fat-suppressed images. Tumors in 12 of 13 patients had regions of high signal intensity on precontrast T1-weighted images. Histology demonstrated intratumoral hemorrhage in all 12 of these patients. Four hemorrhagic tumors were largely cystic on imaging studies. One of these cancers altered in appearance from largely cystic with extensive hemorrhage to largely solid with substantial enhancement after a 2.5-year interval. Renal cancers demonstrated minimal enhancement (11 patients) on early postgadolinium images and were minimally enhanced on delayed images in 10 of 13 tumors. Two renal cancers demonstrated intense enhancement. Renal cancers are well shown on MR images in patients with chronic renal insufficiency. Because of the common occurrence of hemorrhage into renal cancers in patients with renal insufficiency, caution should be exercised when evaluating hemorrhagic cystic lesions in these patients.

Adult↗
PubMedDate not supplied

Liver lesion detection, characterization, and effect on patient management: comparison of single-phase spiral CT and current MR techniques.

This study compares liver lesion detection, characterization, and effect on patient management between single-phase spiral CT and MRI using spoiled gradient echo (SGE), T2-weighted fat-suppressed spin echo, and serial post gadolinium SGE. All patients with suspected liver lesions who underwent spiral CT and MRI within a 1-month period between January 1993 and September 1996 were included in the study. Spiral CT and MRI were interpreted prospectively in a blinded fashion by separate individual experienced investigators, and lesion detection and characterization were determined. Confirmation was obtained by surgery (6 patients), biopsy (18 patients), imaging follow-up (36 patients), or combined reading of all imaging studies and clinical follow-up (29 patients). Effect on patient management was determined by combined chart review and interview of the patients' physicians and by retrospective clinical assessment performed by a surgical oncologist and medical oncologist separately. Eighty-nine patients were included in the study. Regarding true positive lesion detection, 295 and 519 lesions were detected on spiral CT and MR images, respectively, which was significantly different on a patient-by-patient basis (P < .001). More lesions were detected on MR than on spiral CT in 44 of 89 patients (49.4%), and 11 of these 44 patients had lesions shown on MRI in whom no lesions were apparent on CT images. No patients had true positive lesions shown on spiral CT that were not shown on MRI. Regarding lesion characterization, 129 and 466 lesions were characterized on spiral CT and MRI images, respectively, which was significantly different on a patient-by-patient basis (P < .001). More lesions were characterized on MR than CT images in 67 patients (75.3%). Regarding effect on patient management, chart review with physician interview demonstrated that findings on MRI provided information that altered patient management as compared with findings on spiral CT in 57 patients. Retrospective clinical evaluation by the surgical and medical oncologist showed that MRI was considered to have a greater effect on patient management than spiral CT in 58 and 55 patients, respectively. Comparing current MRI technique to single-phase spiral CT, MRI detected more lesions in 49.4% and characterized more lesions in 75.3% of patients investigated for focal liver disease. MRI had a greater effect on patient management in each of the three methods than single-phase spiral CT in more than 61% of patients.

Adolescent↗
PubMedDate not supplied

Comparison of in vivo acute lethal potency and in vitro cytotoxicity of 48 chemicals.

The cytotoxicity of 48 compounds included in the MEIC (Multicenter Evaluation of In Vitro Cytotoxicity) list was determined in cultures of rat hepatocytes, McCoy, and MDBK cells. The average minimum concentration of each compound inducing cytotoxicity was measured in each cell type. The cytotoxicity values were then compared with published oral LD50 values for rats and mice. The logarithmic transformation of in vivo toxic doses and the corresponding in vitro cytotoxic concentrations showed a statistically significant correlation between the in vitro and in vivo values. The results show that an accurate in vivo LD50 dose could be predicted from in vitro data for at least 75% of the selected compounds. It is hoped that this finding will not only stimulate others to pursue in vitro technique but will eventually lead to elimination of the in vivo LD50 test.

Animal Testing Alternatives↗
PubMedDate not supplied

Nephropathy in noninsulin-dependent diabetes mellitus: comparative study with normoproteinuric and microproteinuric subjects.

The role of specific risk factors in the development of diabetic nephropathy was examined among noninsulin-dependent diabetic subjects attending the Diabetes Clinic of Christian Medical College Hospital, Vellore during 1986-87. Seventy-three subjects with normal protein excretion (less than 150 mg/24 hr) were compared with 66 microproteinuric (150-500 mg/24 hr) and 61 macroproteinuric subjects (greater than 500 mg/24 hr). The risk factors included family history of diabetes, tobacco use, dietary habits and metabolic control; the latter was assessed from an average of 5 clinic blood sugar determinations done annually per patient. Patients who had developed proteinuria were characterized as mostly men, with increased tobacco consumption and early onset of proteinuria in relation to duration of diabetes. The mean blood sugar value was significantly high in both the proteinuric groups compared to the group with no proteinuria (p less than 0.01). There was a striking increase in the prevalence of ischemic heart disease, hypertension and retinopathy in the macroproteinuric group compared to the other two groups (p less than 0.01). It is concluded that the risk of developing nephropathy was significantly higher in men, in smokers and in those with poor metabolic control (mean postprandial blood sugar more than 200 mg/dL). Furthermore, it was clearly evident from our study that the diabetic subjects with nephropathy had a higher incidence of hypertension, retinopathy, hyperlipidemia and ischemic heart diseases.

Adult↗