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Biomedical subjects

H G Robson

Publications and source records attributed to H G Robson.

At least 37 records · Page 2Linked to original sources
PubMed1979

In vitro activity of piperacillin compared with that of carbenicillin, ticarcillin, ampicillin, cephalothin, and cefamandole against Pseudomonas aeruginosa and Enterobacteriaceae.

Piperacillin (T-1220), a semisynthetic derivative of aminobenzylpenicillin, was more active than either carbenicillin or ticarcillin against Pseudomonas aeruginosa; over 60% of isolates were inhibited at a concentration of 6.3 mug/ml. Piperacillin was bactericidal for 84% of Pseudomonas strains at 100 mug/ml, carbenicillin killed 60%, and ticarcillin killed 68% at that concentration. Piperacillin was also more active than the other penicillins against isolates of Escherichia coli, Enterobacter, and Proteus mirabilis. The combination of piperacillin and tobramycin, demonstrating synergistic inhibition of 87% of strains of P. aeruginosa, was the most active of the penicillin-aminoglycoside combinations tested for synergism.

Ampicillin↗
PubMed1979

Chlamydia trachomatis genital infections.

The prevalence and clinical features of Chlamydia trachomatis infection were studied in men with nongonococcal urethritis (NGU), in their female sexual partners, and in other women. Of 92 patients with NGU, 36 (39%) were chlamydia-positive; although all had symptoms of urethritis, fewer than half had evident discharge. Clinical features of chlamydia-positive and chlamydia-negative NGU were indistinguishable. Most female contacts of chlamydia-positive patients with NGU were infected with C. trachomatis; contacts of chlamydia-negative patients with NGU seldom harboured chlamydia. Inflammatory and erosive changes were equally common in the uterine cervix of chlamydia-positive and chlamydia-negative women, although almost half of infected cases had no clinical signs of infection and no specific symptoms. In such women the present unavailability of sensitive screening techniques is a major obstacle to the effective control of chlamydial infection.

Adult↗
PubMed1978

Epidemiologic and clinical features of sporadic Salmonella enteric fever.

Twenty-seven cases of enteric fever were diagnosed between January 1961 and February 1977 at a medium-sized urban hospital. Nineteen of the patients had recently travelled abroad. Fever was the only constant finding, and four patients noted fever and headache as their only symptoms. Splenomegaly was present in 30% and rose spots in just 11%. Enteric fever was initially suspected in only 63% of cases, and a mean of 4.8 days elapsed after admission before specific therapy was instituted. Salmonella was cultured from blood samples in 19 of 24 patients and from stool specimens in 21 of 27, but was never isolated from the urine. Serum O agglutinins, while eventually present in 54% of the patients tested, did not help in establishing an early diagnosis. No deaths occurred, though two patients sustained relapses. Sporadic enteric fever is unlikely to be suspected unless associated with recent foreign travel, but is easily diagnosed by usual culture methods.

Adolescent↗
PubMed1978

Cerebrospinal fluid penetration of amikacin.

Adult volunteers underwent a single lumbar puncture 1 to 8.5 h after one 7.5-mg/kg intramuscular amikacin injection. Eighteen showed no detectable drug in cerebrospinal fluid; six had concentrations <0.5 mug/ml.

Adult↗
PubMed1977

Patients' compliance with follow-up after treatment of gonococcal urethritis.

By means of telephone tracing 96% follow-up was achieved in men treated for gonococcal urethritis. A large proportion (34.8%) of patients required one or more calls before follow-up could be obtained. Frequency of sexual re-exposure, proportion with persistent gonorrhea or reinfection, and interval between initial therapy and follow-up were greater in those who required telephone contact for follow-up than in the group who returned for follow-up. Failure to reappear for follow-up does not imply either bacteriologic cure or disappearance of symptoms. Control of gonococcal infection still depends largely upon aggressive methods of case finding, appropriate therapy and careful follow-up.

Anti-Bacterial Agents↗
PubMed1976

Comparative activity of netilmicin, gentamicin, amikacin, and tobramycin against Pseudomonas aeruginosa and Enterobacteriaceae.

Netilmicin (Sch 20569), a semisynthetic aminoglycoside antibiotic, was compared with gentamicin, tobramycin, and amikacin against 242 clinical isolates of Pseudomonas and Enterobacteriaceae. The minimum inhibitory concentration (MIC) was determined in both solid and liquid media. Netilmicin exhibited typical aminoglycoside properties, such as little effect of inoculum size on MIC, relatively small gap between MIC and minimum bactericidal concentration, and potentiation of anti-Pseudomonas activity in the presence of carbenicillin. Netilmicin provided no advantage in antimicrobial activity over gentamicin for either Pseudomonas or Enterobacteriaceae. Nearly complete cross-resistance to netilmicin was encountered with isolates resistant to gentamicin in either solid or liquid media. Netilmicin was less active than gentamicin against isolates of Pseudomonas and Providencia. Major discrepancies between MIC values determined in agar as opposed to those determined in broth were encountered for most isolates of Pseudomonas but also, depending upon antibiotic tested, for between 15 and 40% of isolates of Enterobacteriaceae. This new aminoglycoside agent will be useful clinically only if it is shown to be significantly less toxic than presently available analogues.

Amikacin↗
PubMed1976

Synergistic activity of carbenicillin and gentamicin in experimental Pseudomonas bacteremia in neutropenic rats.

Rats made neutropenic with cyclophosphamide were infected intraperitoneally with Pseudomonas aeruginosa. The challenge organism was killed synergistically in vitro by the combination of gentamicin and carbenicillin. Untreated neutropenic rats infected with 3 x 10(6)Pseudomonas died between days 2 and 7, and the overall mortality was 70%. Groups of infected neutropenic rats were treated intramuscularly with 1.5 or 6 mg of gentamicin per kg per dose, 100 or 400 mg of carbenicillin per kg per dose, or 1.5 mg of gentamicin and 100 mg of carbenicillin per kg per dose. Treatment was begun at 2 h postinfection and was continued every 8 h for about 72 h. Cultures of blood and peritoneal washings were performed in control and treated rats at 1, 4, 24, 48, and 72 h postinfection. Gentamicin at either dose level was ineffective in preventing death, but mortality was significantly reduced by high-dose carbenicillin and low-dose combination therapy. In addition, the latter regimens sterilized the peritoneal fluid and blood. Carbenicillin and gentamicin showed in vivo synergy in the treatment of neutropenic Pseudomonas-infected rats.

Agranulocytosis↗
PubMed1976

Effects of endotoxin on carbohydrate metabolism in inbred mice.

Effects of endotoxin on carbohydrate metabolism were studied in A/HeJ (endotoxin-sensitive) and C3H/HeJ (endotoxin-resistant) inbred mice. A/HeJ mice developed hypoglycemia within two hours after endotoxin injection, yet liver glycogen content did not differ from controls. Similarly treated C3H/HeJ mice did not develop significant hypoglycemia. Administration of glucagon to endotoxin-treated A/HeJ mice failed to elevate their blood glucose concentrations, while endotoxin-treated mice of the same strain did respond to dibutyryl cyclic AMP with a significant elevation of blood glucose. C3H/HeJ mice on the other hand responded to glucagon and dibutyryl cyclic AMP with elevated blood glucose. Endotoxin-treated C3H/HeJ but not A/HeJ mice were able to carry out gluconeogenesis induced by prednisolone, while both inbred strains showed active glycogenesis after administration of an exogenous glucose load. Administration of glucagon resulted in diminished liver glycogen concentrations in A/HeJ endotoxin-treated mice suggesting no impairment of glycogenolysis. The inability of endotoxin-treated A/HeJ mice to respond to glucagon could be due to impairment of gluconeogenesis. Although endotoxin interfered with the capacity of both inbred strains to respond to glucagon administration with elevation of liver cyclic AMP, the effect was significantly more severe in A/HeJ mice. The susceptibility of A/HeJ mice to the lethal effect of endotoxin may be related to the apparent sensitivity of carbohydrate metabolic pathways to disturbance by endotoxin.

Animals↗
PubMed1975

Massive pulmonary gangrene: a severe complication of Klebsiella pneumonia.

SUMMARY: Massive pulmonary gangrene developed in two patients. Review of the literature reveals 10 other case reports of pulmonary gangrene complicating lobar pneumonia. Among the total of 12 patients whose cases have now been reported, all 4 patients who were treated nonsurgically died and the 8 who underwent surgical resection of the gangrenous lung survived. The present report emphasizes the necessity of early recognition and appropriate surgical treatment for a successful outcome.

Adult↗
PubMed1975

Effect of nonspecific stimulation on the defense mechanisms of inbred mice.

Acquired resistance to facultative intracellular parasites was investigated in C57BL/6J inbred mice susceptibe to Salmonella typhimurium but inherently resistant to Listeria monocytogenes and in A/J inbred mice which showed the reverse relationship. A/J but not C57BL/6J mice were protected against S. typhimurium challenge by S. typhimurium phenol vaccine, S. typhimurium purified RNA, or L. monocytogenes purified RNA. C57BL/6J but not A/J could be protected against L. monocytogenes challenge by L. monocytogenes phenol vaccine, S. typhimurium RNA, or L. monocytogenes RNA. Yeast RNA, calf thymus RNA, BCG and poly (I:C) protected A/J against Salmonella and C57BL/6J against Listeria challenge. Enumeration of viable organisms in the RNA and BCG-stimulated animals after challenge indicated that macrophage activation had probably taken place. The RNA-elicited protection was long lasting and waned after about 60 days. Enhanced resistance to S. typhimurium and L. monocytogenes can be stimulated by nonliving substances bearing no known antigenic relationship to the pathogen. Enhanced resistance is elicited only in the host with a background of inherent resistance to the specific pathogen.

Animals↗
PubMed1974

Comparison of amoxicillin and ampicillin in single-dose oral treatment of males with gonococcal urethritis.

Amoxicillin in single oral doses of 2.0 g, 2.0 g plus 1.0 g probenecid, or 3.0 g was compared with ampicillin 3.5 g plus 1.0 g probenecid in the treatment of 203 males with uncomplicated acute gonococcal urethritis. Cure rates above 95% were produced by all treatments except the 2.0-g amoxicillin dose, which cured 89% of patients. Of 198 pretreatment gonococcus isolates tested by an agar dilution technique for susceptibility to penicillin G, ampicillin and amoxicillin, over 50% showed relative resistance (MIC > 0.06 mug/ml) to the antibiotics. However, amoxicillin was somewhat more active against isolates showing considerable resistance (MIC >/= 1.0 mug/ml) to penicillin G or ampicillin. Adverse effects of amoxicillin were few: two patients reported transient nausea and six noted short-lived diarrhea. No hypersensitivity reactions were observed.

Administration, Oral↗
PubMed1974

Single-dose treatment of gonococcal urethritis in males: evaluation of procaine penicillin, ampicillin and spectinomycin.

Males with acute gonococcal urethritis were treated at random with 2.4 million units aqueous procaine penicillin G intramuscularly plus 1.0 g. probenecid orally, 3.5 g. ampicillin orally plus 1.0 g. probenecid orally, or 2.0 g. spectinomycin intramuscularly. The overall follow-up was 97%. All treatments were of equal efficacy, eradication of gonococcal disease being observed in 93 to 97% of treated patients. Treatment failures occurred in each drug group and pre-treatment isolates recovered from these cases showed decreased susceptibility to the agent used. Aqueous procaine penicillin G plus probenecid remains the preferred therapy for gonorrhea. For patients hypersensitive to penicillin, spectinomycin is currently a reasonable alternative drug. This agent, unlike procaine penicillin-probenecid, is probably ineffective against concurrent incubating syphilis, and future development of bacterial resistance is a definite possibility.

Administration, Oral↗
PubMed1972

Susceptibility of Neisseria gonorrhoeae to seven antibiotics in vitro.

One hundred consecutive isolates of N. gonorrhoeae were tested for susceptibility to penicillin, ampicillin, tetracycline, erythromycin, kanamycin, cephaloridine and cephalexin by an agar dilution method. Relative resistance to penicillin was frequent. For 39% of isolates the minimum inhibitory concentration (MIC) of penicillin was 0.05 U./ml. or less; in 55% the MIC was 0.5 to 2.0 U./ml. Ampicillin was slightly more active than penicillin G: all isolates were inhibited by 0.5mug./ml. or less. Resistance to tetracycline and erythromycin was frequent with MIC of 1 mug./ml. or greater observed in 32 and 24% of isolates respectively. The MIC of kanamycin for all gonococci was 8 mug./ml. or greater. Cephalexin was slightly more active than cephaloridine, though each drug exhibited a wide range of MIC values. Gonococcus isolates resistant to penicillin (MIC of 1.0 U./ml. or greater) tended to be resistant to the other antibiotics tested.

Anti-Bacterial Agents↗