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Biomedical subjects

J D Anderson

Publications and source records attributed to J D Anderson.

At least 145 records · Page 8Linked to original sources
PubMed1979

Production and action of ethylene in senescing leaf discs: effect of indoleacetic Acid, kinetin, silver ion, and carbon dioxide.

Supraoptimal concentrations of indoleacetic acid (IAA) stimulated ethylene production, which in turn appeared to oppose the senescence-retarding effect of IAA in tobacco leaf discs. Kinetin acted synergistically with IAA in stimulating ethylene production, but it inhibited senescence. Silver ion and CO(2), which are believed to block ethylene binding to its receptor sites, delayed senescence in terms of chlorophyll loss and stimulated ethylene production. Both effects of Ag(+) were considerably greater than those of CO(2). IAA, kinetin, CO(2), and Ag(+), combined, acted to increase ethylene production further. Although this combination increased ethylene production about 160-fold over that of the control, it inhibited senescence. Treatment with 25 mul/l of ethylene in the presence of IAA enhanced chlorophyll loss in leaf discs and inhibited by about 90% the conversion of l-[3,4-(14)C] methionine to (14)C(2)H(4) suggesting autoinhibition of ethylene production.The results suggest that ethylene biosynthesis in leaves is controlled by hormones, especially auxin, and possibly the rate of ethylene production depends, via a feedback control system, on the rates of ethylene binding at its receptor sites.

Journal Article↗
PubMed1979

Role of bacterial growth rates in the epidemiology and pathogenesis of urinary infections in women.

The mean minimum generation time in shake culture in urine of 6 urinary isolates of Escherichia coli (21.7 +/- 0.6 min) was significantly shorter (P = 0.0003) than that of 14 isolates of less common urinary pathogens (46.0 +/- 18.6 min). Mixed populations of approximately equal numbers of E. coli cells paired with other urinary, fecal, and urethral organisms were introduced into a laboratory model of the lower human urinary tract. This model used urine as a medium and reproduced some features of the balance between bacterial growth and the flushing effect of urine. After 24 h E. coli formed greater than or equal to 99% of the bacterial population in the bladder model for 16 our of 18 pairs of isolates examined. Relatively high oxygen tensions in urine sample from 18 healthy women (10.9 +/- 22. kPA) and 18 infected patients (8.0 +/- 4.3 kPa) may explain why anaerobic urinary infections are uncommon. The rapid growth rate of E. coli may be one explanation why it is the commonest cause of urinary infection even though it is relatively uncommon at the urethral meatus.

Aerobiosis↗
PubMed1979

Urinary excretion of mecillinam by volunteers receiving film-coated tablets of pivmecillinam hydrochloride.

Mecillinam is a new amidinopenicillin which is taken orally as its ester pivmecillinam. 10 healthy volunteers were each given 200 mg of pivmecillinam hydrochloride four times daily and all urine was collected and cooled to -20 degrees C to minimize antibiotic degradation. 43% of the ingested antibiotic was recovered from the urine in its microbiologically active form, during the first 12 h and 34% during the subsequent 24 h. The corresponding figures for 10 volunteers receiving double this dose of antibiotic was 30 and 34%. The mean half life of mecillinam in urine due to spontaneous breakdown at 37 degrees C was 17 h. There was evidence that stearate-film-coated pivmecillinam hydrochloride tablets may be less likely to cause dyspepsia than gelatine capsules.

Administration, Oral↗
PubMed1978

Inhibition of ethylene production in fruit slices by a rhizobitoxine analog and free radical scavengers.

The rhizobitoxine analog, L-2-amino-4-(2-aminoethoxy)-trans-3-butenoic acid (Ro), which effectively inhibits ethylene production in apple (Malus domestica Borkh.) and other tissues at concentrations at about 68 micromolar, inhibited ethylene production by about 50 to 70% in green tomato (Lycopersicon esculentum Mill.) fruit slices but only by about 15% in pink and ripe tomato tissue slices. Ethylene production in climacteric-rise and postclimacteric avocado slices was likewise relatively insensitive to 68 micromolar Ro. At 340 micromolar Ro, inhibition of ethylene production increased up to 50% in pink tomato slices, whereas 680 micromolar Ro was required to inhibit ethylene production by 30% in avocado slices. Incorporation of (14)C from [(14)C]methionine into ethylene in green and pink tomato tissues was inhibited by Ro to about the same extent as inhibition of total ethylene production. Results thus far are inconclusive as to the mechanism of Ro resistance in tomato and avocado tissues. At 1 millimolar, free radical scavengers such as benzoate, propyl gallate, nordihydroguaiaretic acid, and to a lesser extent, eugenol, inhibited ethylene production in both Ro-sensitive (green tomato and apple) tissues and Ro-resistant (pink tomato and avocado) tissues. Therefore, free radical steps are suggested in the ethylene-forming systems.

Journal Article↗
PubMed1978

Speech rehabilitation of a laryngectomized-glossectomized patient.

A 58-year-old English speaking female, who underwent total laryngectomy and glossectomy and subsequently learned to communicate verbally via various phonatory and articulatory compensations, is described in this report. Radiologic study and empirical observation showed her to be using the inhalation method to achieve esophageal air charge. Her articulatory compensations were typical of those used by other glossectomized pateints. The extent of her recovery of verbal communication skills through alaryngeal speech suggests that glossectomized-laryngectomized patients with similar impairment might benefit from speech rehabilitation where prognosis and general health permit.

Female↗
PubMed1977

Renal failure associated with vesicoureteral reflux.

In a review of over 600 charts with a major diagnosis of vesicoureteral reflux only 21 were found to have coexisting azotemia. Nine of 11 patients treated surgically with technically successful operations had either improvement or stabilization of their renal function. All such cases had moderate degrees of azotemia (creatinine of less than 3.5 mg. per 100 ml.). Surgery is recommended in cases of gross reflux and in cases with evidence of parenchymal damage, before deterioration in renal function has become irreversible.

Adolescent↗
PubMed1977

Inflammatory fibrous histiocytoma presenting as a renal pelvic and bladder mass.

The first case of simultaneous presentation of a bladder and renal pelvic malignant fibrous histiocytoma is reported. Although only a small percentage of fibrous histiocytomas are malignant the lesion is extremely aggressive. Radiotherapy and chemotherapy have been used but only sporadic remissions have been reported. If the tumor is localized wide surgical excision is recommended.

Adult↗
PubMed1977

Latent adenocarcinoma in renal cysts.

A case is presented in which repeat examination of a benign cyst disclosed a latent adenocarcinoma near the cyst wall. Since statistically there is a greater incidence of tumor associated with cyst and since there is a 90% accuracy rate in the diagnosis of cystic lesions it appears that reinvestigation seems justified in some cases, especially if there is a change in or new development of symptoms.

Adenocarcinoma↗
PubMed1977

Adenylate metabolism of embryonic axes from deteriorated soybean seeds.

RNA and protein syntheses in axes excised from dry soybean (Glycine max L.) seeds at different levels of deterioration were assayed. Low rates of protein synthesis in slightly deteriorated seeds were not due to losses in ribosomal or soluble fraction activities. However, the lowered rates of RNA and protein syntheses of deteriorated seeds were associated with reduced ATP content of the tissues. Adenine and adenosine conversions to ATP were reduced in deteriorated axes, and these reductions were reflected in reduced incorporation of these compounds into RNA.

Journal Article↗
PubMed1977

Responses of adenine nucleotides in germinating soybean embryonic axes to exogenously applied adenine and adenosine.

The ATP content of soybean (Glycine max [L.] Merr. cv. Kent) axes incubated for 3 hours in 1 mm solutions of adenine and adenosine increased over 100% and 75%, respectively, over axes incubated in water. The increase in ATP was primarily due to the conversion of these purines to nucleotides via the nucleotide salvage pathway. The ATP formed was in a metabolically active pool because label from adenine was incorporated into acid-insoluble material. Adenine also increased the levels of GTP, UTP, and CTP, but not to the extent of the ATP level.

Journal Article↗
PubMed1977

Growth properties of mecillinam-resistant bacterial variants in urine.

Resistant variants are often formed when susceptible Enterobacteriaceae are grown in media containing mecillinam. These variants have not yet been detected in patients or identified as a cause of treatment failure in limited clinical trials. Mecillinam-resistant organisms were formed by 5 out of 13 urinary isolates of Enterobacteriaceae incubated in urine containing mecillinam. The mean generation time of these five variants in urine containing therapeutic concentrations of mecillinam was 3.2 times that of normal organisms in antibiotic-free urine. When three of these five resistant variants were subcultured in antibiotic-free urine, the generation time, morphology, and antibiotic susceptibility returned to normal. On antibiotic-free agar medium, all five mecillinam-resistant variants readily reverted to the "susceptible" form and were therefore more likely to be phenotypic rather than genotypic mutants. In a second series of experiments, the flushing effect of the bladder on the clearance of organisms was partly simulated by frequent subculture in urine. Under these conditions, the cell density of cultures of all bacteria remained high during 10 subcultures over 52 h. However, bacterial populations progressively decreased in urine containing mecillinam until none could be detected at 28 h or thereafter. The slow growth rate of mecillinam-resistant variants may explain why detectable numbers of these organisms fail to colonize the urinary tract during treatment. Other factors may reinforce the postulated effect of the reduced growth rate in vivo.

Amdinocillin↗