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Biomedical subjects

J D Anderson

Publications and source records attributed to J D Anderson.

At least 163 records · Page 9Linked to original sources
PubMed1976

The relevance of growth rates in urine to the pathogenesis of urinary-tract infections due to Micrococcus subgroup 3 (Staphylococcus saprophyticus biotype 3).

A novobiocin-resistant "biotype" of Micrococcus subgroup 3 (Staphylococcus saprophyticus) is known to be a primary pathogen of the female urinary tract and to cause infections as severe as those produced by Escherichia coli. The growth characteristics of this virulent biotype were compared in vitro with those of other Micrococcaceae and of E. coli to determine whether rapid growth explains the virulence of the biotype. Nutrient broth was shown to have growth-supporting qualities that differed from those of urine and it was therefore unsuitable for these studies. In urine, the virulent biotype grew more slowly, had a longer lag period, and reached much lower final viable counts than did Escherichia coli. Surprisingly, the virulent biotype also grew more slowly and reached a lower final viable count than did several other Micrococcaceae isolated from the urinary tract of healthy women. Urine from women who had suffered a recent infection with the virulent biotype had growth-supporting properties similar to those of urine from healthy women. Experiments with filtered forestream urine suggested that urethral secretions do not contain a factor determining growth rates of this organism in urine. The possibility that virulent strains adapt to rapid growth in urine was excluded. No evidence was obtained that the virulent biotype inhibits the growth of other Micrococcaceae in urine. Ability to grow rapidly in urine does not therefore explain the virulence of novobiocin-resistant strains of subgroup-3 micrococci.

Adult↗
PubMed1976

Comparison of the epidemiology of bacterial resistance to mecillinam and ampicillin.

Mecillinam is a new type of beta-lactam antibiotic (an amidinopenicillanic acid) that is particularly active against Enterobacteriaceae and is taken orally as in the form of an ester, pivmecillinam. Assessment of any new antibiotic should include a survey of levels of bacterial resistance and investigation of its capacity to select resistant organisms or harm the commensal flora. Antibiotic resistance patterns of 2,000 Enterobacteriaceae isolated from the urine of patients with significant urinary tract infections were therefore determined. Mecillinam-resistant Enterobacteriaceae were found to be much less common than ampicillin-amoxycillin-resistant organisms both in the community and in hospital patients. Most ampicillin-resistant Enterobacteriaceae from infected urines were susceptible to mecillinam, but the relatively rare mecillinam-resistant organisms were usually resistant to ampicillin and cephaloridine. The fecal flora of 26 healthy volunteers who served as controls or were given repeated courses of therapeutic doses of either ampicillin or pivmecillinam was studied. Pivmecillinam had only a transient effect on the aerobic fecal flora and in contrast to ampicillin did not increase populations of resistant Enterobacteriaceae, which would be a potential hazard to the patient and contaminate the environment.

Ampicillin↗
PubMed1975

Micrococcal urinary-tract infections in young women.

In a prospective study in young women, novobiocin-resistant subgroup-3 micrococci were the second commonest cause, after Escherichia coli; of acute urinary infections. Proteus mirabilis was the only other causative organism. Symptoms, pyuria, or possible aetiological factors were the same in micrococcal and coliform infections. The infecting micrococcus "biotype" was only rarely found among the normal flora of the genitourinary tract of young women, though other micrococci and staphylococci were commonly present. Evidently, the infecting micrococci are selectively pathogenic in the urinary tract. Micrococcal infections, like coliform infections; commonly followed sexual intercourse, but there was no evidence that the micrococci were sexually transmitted. The infecting biotype was rarely found in the male urethra or prepuce.

Drug Resistance, Microbial↗
PubMed1975

Breast feeding and breast cancer.

Clinicians who deal with numerous cases of breast cancer are aware of the fact that there is some relationship between childbearing and breast cancer, and also that nulliparous women are probably more prone to breast cancer than their parous sister. however, a relationship between breast feeding and breast cancer is not certain. This is a preliminary report on a study of the breast feeding habits of breast cancer patients and non-cancerous patients, after an attempt was made to match controls for parity and age.

Adult↗
PubMed1975

Ocular lesions in the Earth Day, 1970, histoplasmosis epidemic.

The relationship between systemic histoplasmosis and this particular clinical picutre of a central choroiditis with peripheral atrophic lesions in the fundus was postulated by Woods in 1960 [19]. Since that time there have been many studies attempting to substantiate his hyptthesis [1, 3-5, 7-18]. In a large study performed in Walkersville, Maryland, which is an area endemic for histoplasmosis [14], the prevalence of the characteristic peripheral histoplasmic lesion in the fundus was 27 per 1000 population. The prevalence was 44 per 1000 population with positive histoplasmosis skin tests. In a similar study done in sothern Ohio, the prevalence of peripheral fundus lesions was 1.6 percent of 1417 patients examined [1]. Several generalizations can be made from the information obtained in studying the students involved in the Willis flu, and these can be compared with information from the control students from Bellingham. First, the acute infection at Willis School did not cause significant ocular abnormalities. This finding is supported by the fact that no significant differences occurred in the fundus lesions seen in the control group of students who lived in the same geographic area but were not clinically ill from histoplasmosis. Our evidence shows that the eyegrounds of the individuals living in this area were different from those of the students who lived outside the central Ohio area. How do we account for the similarity of ocular lesions in the affected students and the Delaware control group? Perhaps by the age of 11 or 12, a person living in the histoplasmosis belt will have already been exposed to histoplasmosis, resulting in the characteristic scars that are seen. If, in fact, histoplasmosis is the etiological agent in the patients who are diagnosed as having presumed ocular histoplasmosis, difficulty arises in understanding why those individuals involved in the epidemic did not have more scars than the control group. Perhaps the numbers of patients examined were not large enough to reflect the difference that really may exist. An interesting observation is that 4 (67 percent) of our control students with significant lesions had negative histoplasmosis skin tests. Of course, other organisms may have caused these lesions which have not yet been implicated as causative agents in the presumed ocular histoplasmosis syndrome.

Adolescent↗
PubMed1975

Factors that may prevent transfer of anti-biotic resistance between gram-negative bacteria in the gut.

Antibiotic-resistance transfer between populations of donor and recipient strains of Escherichia coli was completely inhibited in broth by dense suspensions of Bacteroides fragilis. Comparable amounts of inert bacterial matter (for-molised suspensions of E. coli or B. fragilis), or smaller numbers of viable B. fragilis, Streptococcus faecalis, Staphylococcus albus, Neisseria catarrhalis, or solutions of sodium taurocholate or glycocholate were only moderately inhibitory. Anaeroboisis had no effect upon plasmid transfer. Population densities of enteric organisms in these studies were similar to those found in faeces. The presence of dense cultures of B. fragilis provide a satisfactory explanation for almost total inhibition of conjugation in the human gut. Other factors inhibiting conjugation to a lesser degree may reinforce the effect of B. fragilis in vivo. As well as selecting for resistant organisms, antibiotics may also indirectly increase populations of R factor-bearing organisms in the gut by interfering with the anaerobic flora and so permit an increase in the frequency of conjugation.

Anaerobiosis↗
PubMed1975

The effects of overstretching on the structure and function of the bladder in relation to Helmstein's distension therapy.

Measurements of the maximum bladder distensibility, cystometrograms and histological studies of the bladder after Helmstein's distension therapy show intramural fibrosis and a reduction in bladder capacity. When this is made worse by post-radiation fibrosis it may give rise to such severe contraction that diversion may be needed. There is no evidence that distension, of the type used here, ever gives rise to "stretching" or "atony" of the bladder: and it is questionable whether distension of a lesser degree, such as may be found in acute urinary retention, ever does so either.

Dilatation↗
PubMed1975

The therapeutic application of hyperthermia in the bladder.

Experience with 10 cases of hyperthermic irrigation of the bladder suggests that irrigation with saline at 80 degrees C for 10 to 15 min will stop bleeding and destroy epithelium and muscle layers without causing visceral injury or systemic disturbance. It may be preferable to cystectomy in certain poor-risk patients, or in those who refuse cystectomy for fear of impotence.

Aged↗