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Biomedical subjects

M May

Publications and source records attributed to M May.

At least 289 records · Page 16Linked to original sources
PubMedDate not supplied

MRX8: an X-linked mental retardation condition with linkage to Xq21.

A family in which 6 males have X-linked mental retardation has been studied with polymorphic DNA probes. The males differ from unaffected males only in impaired intellect and in smaller head size. The gene that causes mental retardation in the family appears to be located in band Xq21 on the basis of linkage with 3 markers: DXS250, DXS345 and DXS3 (theta max = 0.00; Zmax = 1.6). A multipoint lod score of 2.36 was obtain with no recombination relative to DXS326 in Xq21. This family is considered to have nonspecific X-linked mental retardation and has been given the designation MRX8.

Adult↗
PubMedDate not supplied

The isolation of functionally heterogeneous hepatocytes of the proximal and distal half of the liver acinus in the rat.

The objective of this study was to isolate hepatocytes of the proximal half (Zones 1 and 2) or distal half (Zones 2 and 3) of the liver acinus. The zonal origin of the isolated hepatocytes was recognized by: the presence in hepatocytes of a fluorescent marker, acridine orange, selectively delivered to either the proximal or the distal half of the acinus by in situ perfusion prior to cell isolation and the measurement of the induction of cytochrome P-450 by phenobarbital, an induction known to occur predominantly in the distal half of the acinus. Following the selective labeling of the acinus with acridine orange, livers were perfused with collagenase in either the portal to hepatic vein direction (anterograde) or in the retrograde direction. Hepatocytes isolated by either an anterograde or a retrograde perfusion were separated by centrifugation in a Percoll density gradient. This procedure isolated populations of proximal or distal hepatocytes, respectively, which were intact and 90% fluorescent. In an effort of assessing the heterogeneity of the separated proximal and distal hepatocytes, each population was further fractionated by centrifugal elutriation. This resulted in the arbitrary separation of proximal or distal hepatocytes into five fractions. Total cytochrome P-450 was determined spectrophotometrically in each of the fractions isolated from controls and after 3 days of the in vivo administration of phenobarbital. On the basis of the pattern of fluorescence in isolated hepatocytes and on the cytochrome P-450 inductive response to phenobarbital administration, it is proposed that: the anterograde or retrograde perfusion of the liver with collagenase separated hepatocytes predominantly of the proximal or distal half of the liver acinus, respectively and that hepatocytes of the distal half of the liver acinus responded to phenobarbital administration with the highest level of cytochrome P-450 induction, indicating that the isolated hepatocytes conserved the functional heterogeneity observed in vivo.

Acridine Orange↗
PubMedDate not supplied

Heterogeneous expression of phenobarbital-inducible cytochrome P-450 genes within the hepatic acinus in the rat.

Within the hepatic acinus, the functional unit of liver parenchyma, the induction of cytochrome P-450 protein by phenobarbital is manifested primarily in hepatocytes located closer to the hepatic venule, i.e., distal hepatocytes. The objective of this study was to determine the levels of cytochromes P-450b and P-450e mRNAs in populations of hepatocytes originating in the proximal or distal half of the liver acinus in the rat, as an approach to the elucidation of the mechanisms responsible for the heterogeneous zonal expression of cytochrome P-450 protein. The development of a new method to isolate hepatocytes originating from the proximal or distal half of the liver acinus enabled the measurement of total cytochrome P-450 content and of cytochromes P-450b and P-450e mRNAs in these hepatocytes. Levels of cytochromes P-450b and P-450e mRNAs were assessed in proximal and distal hepatocytes by Northern blot hybridization of poly(A+)RNA with a cDNA recognizing sequences of these two cytochromes. The kinetics of induction were defined by measuring these parameters after a single phenobarbital injection. Cytochrome P-450 mRNA levels reached maximum induction at 16 hr, returning to basal values by 48 hr. In contrast, total cytochrome P-450 microsomal protein content reached maximum induction after 33 hr. Hepatocytes of the distal half of the hepatic acinus responded to phenobarbital with higher levels of cytochromes P-450b and P-450e mRNAs than proximal hepatocytes. These results indicated that there is modulation of the expression of the cytochromes P-450b and P-450e genes within the hepatic acinus.

Animals↗
PubMedDate not supplied

Pseudo food allergy.

Hydatid disease is a common zoonosis caused by the larval cysts of Echinococcus granulosus (parasitic tapeworm). In children, lung hydatid cysts are more common than liver cysts, whereas in adults the reverse is true. Pulmonary hydatids can be accompanied by concurrent liver cysts. Leakage or rupture of a hydatid cyst can cause allergic reactions including anaphylaxis. Albendazole is effective therapy either alone or as an adjunct to surgery.

Albendazole↗
PubMedDate not supplied

Management of cranial nerves I through VII following skull base surgery.

Cranial nerve injuries are common with skull base surgery. While injuries to the seventh and tenth cranial nerves can be corrected to satisfactory degrees, rehabilitation of the third, fourth, and sixth nerves is possible to only a limited degree. This study stresses the management of facial paralysis following skull base surgery and is based upon the author's experiences in dealing with 38 patients who suffered such a facial paralysis. The best results of rehabilitative surgical treatment were achieved with techniques that connect the central stump to the peripheral system. The time between nerve injury and repair was the most significant determinant of the success of the surgical procedure: when the nerve was repaired within three months of the injury, the best results were obtained; when the central stump was not available or the injury was more than two years old, repair was not as satisfactory. In the latter case the procedure of choice was the 12th-7th nerve hookup. Indications and results of facial nerve grafting, cross faciofacial nerve hookups, muscle swings, free muscle implantations, and eye reanimation techniques are discussed.

Abducens Nerve Injury↗
PubMedDate not supplied

Facial paralysis in children: differential diagnosis.

The differential diagnosis in 170 patients between birth and 18 years of age is reviewed. There are a number of obvious physical findings and historical features that allow one to make a diagnosis rather quickly. Pain, vesicles, a red pinna, vertigo, and sensorineural hearing loss suggest herpes zoster oticus. Slow progression beyond three weeks, recurrent facial paralysis involving the same side, facial twitching, weakness, or no return of function after six months indicate a neoplasm. Bilateral simultaneous facial paralysis indicates a cause other than Bell's palsy, such as Guillain-Barré syndrome, pseudobulbar palsy, sarcoidosis, and leukemia. Recurrent facial paralysis associated with a fissured tongue, facial edema, and a positive family history should suggest Melkersson-Rosenthal syndrome.

Abnormalities, Multiple↗