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Biomedical subjects

J K Freeman

Publications and source records attributed to J K Freeman.

At least 19 recordsLinked to original sources
PubMed2001

Combined carcinoid tumor and ganglioneuroblastoma of the lung: a case report.

Carcinoid tumor is a well-differentiated epithelial neuroendocrine neoplasm which is common in the lung. Ganglioneuroblastoma is a moderately differentiated nonepithelial neuroendocrine neoplasm which is very rare in the lung. Neuroendocrine tumors with epithelial and nonepithelial elements are rare in any site and have not been reported in the lung. This case is an example of a primary neuroendocrine lung tumor combining epithelial and non-epithelial components: carcinoid tumor and ganglioneuroblastoma.

Aged↗
PubMed2000

Inflammatory pseudotumour of the pancreas in a child.

We describe a 4-year-old girl with an inflammatory pseudotumour of the pancreas, which was preceded by varicella-zoster infection. Inflammatory pseudotumour may involve a variety of tissues, the lungs and liver being typical sites of predilection. Imaging and laboratory tests are nonspecific, and for this reason the diagnosis of inflammatory pseudotumour is rarely made prior to surgery. These benign but locally aggressive masses simulate malignancy in the majority of cases. Inflammatory pseudotumour should, therefore, be considered when a mass arises in an unusual location in the paediatric age group.

Chickenpox↗
PubMed2000

Malrotation with recurrent volvulus presenting with cholestasis, pruritus, and pancreatitis.

A patient aged 16 years was referred following numerous episodes of intense pruritus associated with persistently altered liver function tests. Ultrasound (US) demonstrated the superior mesenteric vein positioned more to the left than usual and abnormal orientation of the duodenum, consistent with a midgut malrotation. Endoscopic retrograde cholangiopancreatography the common bile duct, suggesting a malrotation with chronic or recurrent volvulus. A classic malrotation with 180 degrees volvulus was noted at operation. A second child previously thought to have recurrent idiopathic pancreatitis was noted to have ampullary distortion secondary to malrotation following presentation with an intestinal obstruction. Pruritus and pancreatitis have not been previously reported with malrotation, although cholestatic jaundice has been described. The diffculties in diagnosis and the role of US are discussed. Ladd's procedure is the appropriate treatment for this condition.

Adolescent↗
PubMed1998

Experience with a new technique of primary gastrostomy button placement in association with the Nissen fundoplication.

The tube gastrostomy has always been associated with significant morbidity, mainly because of difficulty in immobilisation, resultant dislodgement, and problems with replacement. Between January and October 1994, we employed a method of primary button gastrostomy in 18 patients with excellent results. Complications have been minimal. There has been no incidence of intra-peritoneal gastric leakage, wound infection, or button dislodgement. Two patients have had peristomal ulceration.

Female↗
PubMed1997

A new instrument for suction rectal biopsy in the diagnosis of Hirschsprung's disease.

A new instrument for suction rectal biopsy in infants suspected of having Hirschsprung's disease is described that can be completely dismantled, physically cleaned, lubricated, and heat-sterilised. These attributes are new and are absolutely critical today. The instrument has been used in 60 patients (ca. 180 biopsies) from 1988 to 1994. A successful biopsy was usually achieved and no major complications occurred. Recently, a second biopsy capsule with a larger port has been added, thus enhancing the versatility of the instrument. The original instrument has never been sharpened or repaired and is still in use. A direct descendant of this prototype instrument is now commercially available.

Adolescent↗
PubMed1997

Idiopathic focal foveolar hyperplasia in infants.

Idiopathic focal foveolar hyperplasia (FFH) is a rare cause of gastric outlet obstruction in infants. We present two cases, including the first reported association with infantile hypertrophic pyloric stenosis. The diagnostic ultrasound appearance of FFH is described. Optimal treatment is surgical excision of the involved mucosa with pyloroplasty or pyloromyotomy.

Diagnosis, Differential↗
PubMed1994

Heterodimerization of epidermal growth factor receptor and wild-type or kinase-deficient Neu: a mechanism of interreceptor kinase activation and transphosphorylation.

We have shown that members of the erbB family undergo homodimer and heterodimer formation. The rat p185c-neu and the epidermal growth factor receptor (EGFR) can associate into an active heterodimeric tyrosine kinase. Overexpression of these two receptors also results in a transformed phenotype. We now show that mutant Neu proteins resulting from a point mutation at the ATP-binding site (N757) or cytoplasmic domain deletions (N691stop) are still able to undergo EGF-induced heterodimerization with EGFR. Analysis of heterodimer formation between EGFR and truncated Neu proteins revealed that heterodimerization is preferred over homodimerization of EGFR. N757 can be transphosphorylated by associated EGFR upon EGF stimulation. However, the heterodimer composed of EGFR and N691stop is kinase inactive. These results provided evidence that the Neu ectodomain is sufficient to associate with EGFR physically, and the cytoplasmic domain interaction is required for heterodimeric kinase activation, indicating that Neu/c-erbB2 is not just a simple substrate for EGFR but a transactivator as well.

Animals↗
PubMed1994

Confocal microscopic visualization of MK-801-induced cytoplasmic vacuoles in vitro.

We examined neuroprotective and neurotoxic effects of the NMDA antagonist, MK-801, in primary cell cultures derived from embryonic mouse neocortex. Brief deprivation of oxygen and glucose, or direct application of N-methyl-D-aspartate (NMDA), resulted in acute neuronal swelling followed by neuronal death during the next day. This excitotoxic neuronal injury could be blocked by inclusion of a wide variety of NMDA antagonists in the cell culture medium. MK-801 attenuated neuronal death in the low micromolar range; 1 to 10 microM concentrations were sufficient to maximally reduce injury from NMDA toxicity, oxygen deprivation, or combined deprivation of oxygen and glucose. MK-801 alone caused no apparent toxicity at these concentrations in exposures of 24 to 48 hours. However, 24-hour exposure to 100 microM MK-801 resulted in appearance of cytoplasmic vacuoles, which could be visualized with immunofluorescence against the microtubule associated protein, MAP2, together with laser scanning confocal microscopy. Thus, at concentrations sufficient to block NMDA receptors, MK-801 is neuroprotective rather than neurotoxic for cortical neurons in vitro. This model system may provide a method to examine cellular mechanisms underlying the neurotoxicity of MK-801 at very high concentrations.

Animals↗
PubMed1993

Modeling physicians' prescribing decisions for patients with panic disorder.

The authors asked general and family practitioners to rate the importance of several items relating to the prescribing of drug products for patients with panic disorder. Physicians preferred to use benzodiazepines alone and in combination with antidepressants for treatment, regardless of the presence or absence of phobic avoidance. Adverse drug events, efficacy, and patient characteristics were found to be important considerations when physicians prescribe medication. Educational and promotional strategies for pharmaceutical manufacturers and marketers are discussed.

Antidepressive Agents↗
PubMed1991

Characterization of a neu/c-erbB-2 protein-specific activating factor.

The neu oncogene encodes a tyrosine kinase with growth factor receptor-like properties. A neu protein-specific activating factor (NAF) was partially purified from medium conditioned by the transformed human T-cell line ATL-2. NAF was able to stimulate the tyrosine-specific kinase activity of the neu protein (p185neu), induce dimerization and internalization, and increase the growth of cells bearing the neu protein. The effects of NAF were mediated by an interaction with the p185neu extracellular domain. NAF had no effect on the epidermal growth factor receptor kinase activity and no effect on cells that express that receptor. Further analysis of NAF and of other recently described neu protein-activating activities should help clarify the role of the neu protein in cell growth and transformation.

Cell Division↗
PubMed1985

Supraclavicular approach to cervical esophageal atresia with tracheoesophageal fistula.

This is a report of a patient with esophageal atresia with a blind upper pouch and a lower pouch fistula, both in the neck. The preoperative radiologic appearance of an air-filled esophagus behind the trachea suggested a higher than normal fistula. Preoperative bronchoscopy confirmed the cervical position of the fistula and, as a result, a supraclavicular incision was used to approach both the atresia and fistula.

Esophageal Atresia↗