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J Nash

Publications and source records attributed to J Nash.

87 records · Page 5Linked to original sources
PubMed1976

Racemic diastereoisomers of 1-amino-2-hydroxycyclopentanecarboxylic acid.

The synthesis and characterization of the two diastereoisomeric forms of 1-amino-2-hydroxycyclopentanecarboxylic acid have been accomplished. A previously reported synthesis produced a racemic mixture of the threonine analog trans-2-hydroxy-1-aminocyclopentanecarboxylic acid (trans with respect to the hydroxy and carboxyl group). The alternate allothreonine analog was produced by conversion of cyclopentene oxide to trans-2-methoxycyclopentanol, followed by oxidation to 2-methoxycyclopentanone and conversion to a hydantoin. Fractional crystallization of the hydantoin sample, followed by hydrolysis, produced cis-2-hydroxy-1-aminocyclopentanecarboxylic acid (cis with respect to the hydroxy and carboxyl group) in high purity. Neither of the isomeric forms significantly inhibited the growth of the bacterial strains examined nor were they effective in inhibiting Jensen sarcoma cells in tissue culture.

Amino Acids↗
PubMedDate not supplied

Value of grading squamous cell carcinoma of the head and neck.

We report a series of 3,294 patients with squamous cell carcinoma of the head and neck seen by one of us between 1963 and 1990. Two thousand and seven patients had a histologically proven and graded, but previously untreated, squamous cell carcinoma of the mucosal surfaces of the head and neck. These tumors had been graded previously by many different pathologists in many different hospitals, both in the United Kingdom and the United States, as well as continental Europe, over this period. Of the host factors both sex and age were associated with differentiation: 34% of patients less than age 50 had a well-differentiated tumor compared with 44% greater than age 50; 32% of women had a poorly differentiated tumor compared with 26% of men. General condition had no correlation with degree of differentiation. Site was closely associated with grading: well-differentiated tumors were more common in the mouth and larynx and poorly differentiated tumors in the pharynx. Furthermore, of poorly differentiated tumors, 19% arose from areas normally lined by keratinized squamous epithelium, 22% from a nonkeratinized area, 36% from respiratory epithelium, and 45% from areas normally covered by lymphoid epithelium. T stage had no significant correlation with differentiation. However, 46% of patients with poorly differentiated tumors had a nodal metastasis at presentation compared with only 28% of well-differentiated tumors. Distant metastases at presentation were found in 3.4% of poorly differentiated tumors compared with 1.8% of well-differentiated tumors. The survival fell significantly from 33% for well-differentiated tumors to 27% for poorly differentiated tumors. The recurrence rate at the primary site rose from 25% for well-differentiated tumors to 27% for poorly differentiated tumors, and recurrence in the lymph nodes rose from 26% to 30%. Both differences were just significant.

Adolescent↗