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D Corbin

Publications and source records attributed to D Corbin.

17 recordsLinked to original sources

Clinical and laboratory features of adult T-cell leukaemia lymphoma in Barbados.

We describe the clinical and pathological features of 23 Afro-Caribbean patients with adult T-cell leukaemia/lymphoma admitted to the Queen Elizabeth Hospital, Barbados over a 5 year period. There were 9 males and 14 females, with a median age of 38 years (range 14-84). Twelve had acute leukaemia, 10 lymphoma (including 4 with solitary extra nodal lesions) and 1 smouldering subtype. Two patients had a past history of tropical spastic paraparesis/HTLV I associated myelopathy (TSP/HAM). The prognosis was poor, with only 3 complete responses to chemotherapy (CHOP) lasting from 9 to 36 months. We conclude that ATLL in Barbados is similar to the disease in the other Caribbean islands and Japan, except that in Barbados the age of onset is over a decade younger than in Japan.

Adolescent

Age-specific reference ranges for serum prostate-specific antigen.

OBJECTIVES: To assess the relationship of the distribution of serum prostate-specific antigen (PSA) to age in a population of subjects for whom PSA levels were determined as part of a health fair. METHODS: Between March 19 and March 28, 1993, 1716 men aged 40 to 79 years from eastern Nebraska who participated in "The Health Fair of the Midlands" provided blood for serum PSA determination. RESULTS: Serum PSA concentration was correlated with patient age, with the observed 95th percentile increasing from 1.5 ng/mL for subjects 40 to 44 years of age to 7.7 ng/mL for subjects 75 to 79 years of age. Variability in serum PSA concentrations increased with increasing age. Taking this heteroscedasticity into account provided the following upper limits of normal (95th percentiles) for serum PSA: age 40 to 49, 1.5; age 50 to 59, 2.6; age 60 to 69, 4.4; age 70 to 79, 7.5. CONCLUSIONS: Previously published age-specific reference ranges did not consider the increasing variability of PSA concentration with age and have upper limits of normal that are too high for subjects under age 60 and may be too low for subjects aged 70 to 79. Upper reference ranges of 1.5 ng/mL for subjects aged 40 to 49, 2.5 ng/mL for subjects aged 50 to 59, 4.5 ng/mL for subjects aged 60 to 69, and 7.5 ng/mL for subjects aged 70 to 79 years provide specificity near 95%.

Adult

Central neurocytoma: An unusual intraventricular tumor.

A case of central neurocytoma occurring in a 22-year-old man is presented. This tumor is generally considered to be benign in appearance, nonrecurrent, and amenable to surgical resection. However, this particular neurocytoma demonstrated anaplastic features, raising the issue of malignancy and the need for additional modes of treatment. Implicated factors and possible optimal treatment for this tumor are discussed.

Adult

Focal seizures and non-ketotic hyperglycaemia.

The clinical features of seven patients with non-ketotic hyperglycaemia who developed focal seizures are presented. All patients were alert except one who was mildly confused. Glucose values varied from 17.8 to 55.1 mmol/l, while calculated osmolarity values were elevated in all cases to a mild or moderate extent (299.1 to 346.5 mmol/l). In three cases diabetes mellitus was a new diagnosis. Four patients had recurrent episodes of focal seizures when glycaemic control was lost. Movement induced or kinesigenic seizures were seen in three cases and epilepsia partialis continua in one case. Seizures associated with hyperglycaemia are resistant to anticonvulsant treatment and respond best to insulin and rehydration. Focal seizures in adults may indicate diabetes mellitus.

Adult

Erythropoietic protoporphyria: unusual skin and neurological problems after liver transplantation.

The case of a woman with protoporphyria who developed liver failure and underwent liver transplantation is described. During the pretransplant episode of liver failure she developed quadriparesis that rapidly progressed after transplantation to a severe polyneuropathy. Following transplantation she also developed a second-degree burn of the light-exposed abdominal wall. The neuropathy resembled that observed in other forms of porphyria, and it is proposed that the extreme disturbance of protoporphyrin levels associated with protoporphyrin-induced liver failure caused this neuropathy. Such a neuropathy has not previously been described in protoporphyria. Erythrocyte protoporphyrin levels remain high and fecal levels normal, although results of liver tests are normal. She remains photosensitive, which emphasizes that although liver transplantation may be lifesaving in this disorder, it is not curative, and care must be taken to prevent photosensitive damage to skin and light-exposed internal organs.

Adult

Migraine coma.

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Adolescent

The influence of mevinolin on the adrenal cortical response to corticotropin in heterozygous familial hypercholesterolemia.

The biosynthesis of adrenal corticosteroids in humans depends on a continuous supply of cholesterol, which can be derived from both local synthesis and receptor-mediated uptake of low density lipoproteins (LDL) from plasma. Mevinolin, an inhibitor of 3-hydroxy-3-methylglutaryl-CoA reductase [mevalonate:NAD+ oxidoreductase (CoA-acylating), EC 1.1.1.88] is an effective hypolipidemic agent in patients with heterozygous familial hypercholesterolemia. To determine whether mevinolin influences the adrenal production of corticosteroids, the adrenocortical response to a continuous 36-hr infusion of corticotropin (ACTH) was examined in eight patients with heterozygous familial hypercholesterolemia before, and again during, treatment with mevinolin (40-80 mg/day). The drug produced an average decrease of 28% and 34% in the plasma concentrations of total and LDL cholesterol. Serum cortisol levels showed similar increases in response to ACTH stimulation before and during mevinolin treatment, and the rates of excretion of urine-free cortisol were also similar. We conclude that clinically effective doses of mevinolin do not affect corticosteroid production by the adrenal cortex during prolonged ACTH stimulation in patients with heterozygous familial hypercholesterolemia.

Adrenal Cortex

Structural relationships among Rhizobium meliloti symbiotic promoters.

Symbiotic nitrogen fixation by Rhizobium meliloti requires the developmentally specific expression of certain bacterial genes. One set of these genes encodes the subunits of nitrogenase, the enzyme responsible for the reduction of atmospheric dinitrogen to ammonia, and another set consists of closely linked genes also essential for nitrogen fixation. Examination of promoter and probable regulatory regions for these gene sets has revealed extensive DNA sequence conservation for more than 160 bp upstream of the respective transcription start points. Three such promoter regions have been identified in the nitrogen fixation (nif) gene cluster of R. meliloti strain 102F34. Using one of these promoter regions as a hybridization probe, three additional sequences were found in the genome of this strain. The DNA of other R. meliloti strains and Rhizobium species were also examined for homology to the symbiotically regulated promoters of R. meliloti 102F34. DNA sequences homologous to these R. meliloti promoters were found among diverse rhizobia, and in at least some cases were associated with nif genes.

Base Sequence

Clustering of nitrogen fixation (nif) genes in Rhizobium meliloti.

A cloned 17.3-kilobase region of the Rhizobium meliloti genome with homology to the Klebsiella pneumoniae nitrogenase structural genes was studied. Limits on the extent of homology were determined. Transposon mutagenesis of this region of the genome verified that it contained functional nif genes, Some transposon insertions resulted in a defective symbiotic phenotype, whereas others had no noticeable effect on symbiotic competence. The relative position of insertions yielding these two phenotypic classes suggested that at least three distinct units of gene expression are present in this region. Hybridization of RNA from alfalfa root nodules and from vegetatively grown Rhizobium to this cloned DNA showed that at least 11.1 kilobases of the region was transcribed actively and that transcription was specific for the symbiotic state.

Cloning, Molecular

Broad host range DNA cloning system for gram-negative bacteria: construction of a gene bank of Rhizobium meliloti.

A broad host range cloning vehicle that can be mobilized at high frequency into Gram-negative bacteria has been constructed from the naturally occurring antibiotic resistance plasmid RK2. The vehicle is 20 kilobase pairs in size, encodes tetracycline resistance, and contains two single restriction enzyme sites suitable for cloning. Mobilization is effected by a helper plasmid consisting of the RK2 transfer genes linked to a ColE1 replicon. By use of this plasmid vehicle, a gene bank of the DNA from a wild-type strain of Rhizobium meliloti has been constructed and established in Escherichia coli. One of the hybrid plasmids in the bank contains a DNA insert of approximately 26 kilobase pairs which has homology to the nitrogenase structural gene region of Klebsiella pneumoniae.

Cloning, Molecular