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Biomedical subjects

D E Townsend

Publications and source records attributed to D E Townsend.

At least 37 records · Page 2Linked to original sources
PubMed1992

Synchronous radiation and cytotoxic chemotherapy for locally advanced or recurrent squamous cancer of the vulva.

Between July 1987 and September 1991 a program of external beam radiation and synchronous, radiopotentiating chemotherapy was employed to treat 25 women with locoregionally advanced or locoregionally recurrent squamous cancer of the vulva. Of 18 previously untreated patients, 1 was Stage II, 10 were Stage III, 6 were Stage IVA, and 1 was Stage IVB. Reasons for patient referral for nonsurgical management included the presence of initially unresectable disease (5 patients), disease extent which would have necessitated partial or total exenteration if treated surgically (9 patients), disease extent predictive of inadequate surgical margins (less than 1 cm gross margin) if treated by less than exenterative surgery (8 patients), and severe comorbid illness precluding surgical management (3 patients). Complete clinical response was obtained in 16 of 18 previously untreated patients (89%) and in 4 of 7 patients with recurrent disease following vulvar surgery (57%). Of 20 patients achieving a complete clinical response, 3 patients have relapsed within the irradiated volume at 11, 38, and 48 months following completion of treatment. Fourteen patients remain alive and continuously cancer free from 2-52 months after completion of treatment (median follow-up 24 months). This experience suggests that initial management with radiation and chemotherapy may offer some patients with locally advanced squamous cancer of the vulva an alternative to exenterative surgery and may hold curative potential for some patients with surgically unresectable or medically inoperable disease.

Adolescent↗
PubMed1992

Proline transport in Staphylococcus aureus: a high-affinity system and a low-affinity system involved in osmoregulation.

L-Proline enhanced the growth of Staphylococcus aureus in high-osmotic-strength medium, i.e., it acted as an osmoprotectant. Study of the kinetics of L-[14C]proline uptake by S. aureus NCTC 8325 revealed high-affinity (Km = 1.7 microM; maximum rate of transport [Vmax] = 1.1 nmol/min/mg [dry weight]) and low-affinity (Km = 132 microM; Vmax = 22 nmol/min/mg [dry weight]) transport systems. Both systems were present in a proline prototrophic variant grown in the absence of proline, although the Vmax of the high-affinity system was three to five times higher than that of the high-affinity system in strain 8325. Both systems were dependent on Na+ for activity, and the high-affinity system was stimulated by lower concentrations of Na+ more than the low-affinity system. The proline transport activity of the low-affinity system was stimulated by increased osmotic strength. The high-affinity system was highly specific for L-proline, whereas the low-affinity system showed a broader substrate specificity. Glycine betaine did not compete with proline for uptake through either system. Inhibitor studies confirmed that proline uptake occurred via Na(+)-dependent systems and suggested the involvement of the proton motive force in creating an Na+ gradient. Hyperosmotic stress (upshock) of growing cultures led to a rapid and large uptake of L-[14C]proline that was not dependent on new protein synthesis. It is suggested that the low-affinity system is involved in adjusting to increased environmental osmolarity and that the high-affinity system may be involved in scavenging low concentrations of proline.

Biological Transport↗
PubMed1991

Vasopressin and operative hysteroscopy in the management of delayed postabortion and postpartum bleeding.

Two women, one with refractory postabortion hemorrhage and the other with refractory postpartum hemorrhage, were managed with vasopressin, operative hysteroscopy, and a dilute vasopressin pack. Both patients had been treated by standard methods (i.e., dilation and curettage) and both were being prepared for a surgical intervention procedure. It was decided in both cases to try to slow the bleeding by injection of vasopressin paracervically and then performance of operative hysteroscopy. In both cases, the injection of dilute vasopressin paracervically when coupled with operative hysteroscopy was quite effective in determining the cause of the bleeding and was instrumental in avoiding major operative procedures.

Abortion, Induced↗
PubMed1991

Vasopressin pack for treatment of bleeding after myoma resection.

In 17 women with refractory bleeding after myoma resection a dilute vasopressin pack was applied. Twenty units of vasopressin was diluted with 30 ml normal saline solution. A 1-inch new gauze pack was soaked in the dilute vasopressin and packed into the uteri of patients with bleeding from the beds of resected submucous myomas. The pack was left in place for no more than an hour. In none of the cases was there bleeding after the removal of the pack nor were there any side effects that could be attributed to the vasopressin.

Administration, Intravaginal↗
PubMed1990

Laminaria tent for diagnostic and operative hysterectomy.

Laminaria tents were inserted in 300 nonpregnant women to induce cervical dilation before diagnostic or operative hysteroscopy. All laminaria tents were inserted without anesthesia following uterine sounding. Diagnostic hysteroscopic procedures were performed with a 5.0 mm hysteroscope with video monitoring within 2-3 hours after insertion of the laminaria tent. Minimal analgesia was used. Operative procedures were performed approximately 24 hours after insertion of the laminaria tent with a 9 mm operative resectoscope. There were no complications with the use of the laminaria tent, such as infections or bleeding, but a few patients complained of mild menstrual-like lower abdominal discomfort. In all cases, the laminaria tent resulted in a softening and dilation of the cervix, which facilitated the passage of the diagnostic and operative hysteroscope.

Adult↗
PubMed1990

"Rollerball" coagulation of the endometrium.

Menorrhagia was the primary complaint of 50 patients treated by "rollerball" electrocoagulation of the endometrium. All the patients in this series had failed surgical (D & C) and/or medical therapy and all had refused hysterectomy. The electrocoagulation was performed on an outpatient basis. Complications have been minimal with follow-up varying from 6-22 months. Amenorrhea was achieved in ten of the 25 women who were followed for at least 12 months. An additional ten patients have had monthly spotting and five have had light bleeding. None of the patients noted a return of their menorrhagia. In the other 25 patients bleeding could not be evaluated, as all received medroxyprogesterone after their ablation. The preliminary results suggest that "rollerball" electrocoagulation is a safe, economical, and effective method of eliminating or reducing menorrhagia.

Combined Modality Therapy↗
PubMed1987

The international spread of methicillin-resistant Staphylococcus aureus.

A genetic analysis of representative methicillin-resistant Staphylococcus aureus (MRSA) being isolated in London and Dublin hospitals has demonstrated that the epidemic strains from two London hospitals are different from the Dublin strains, but indistinguishable from the epidemic strains of eastern Australia. The possibility that some strains of MRSA are more likely than others to spread within hospitals is discussed.

Australia↗
PubMed1986

Conjugative, staphylococcal plasmids carrying hitch-hiking transposons similar to Tn554: intra- and interspecies dissemination of erythromycin resistance.

Two staphylococcal plasmids, pWG4 and pWG25, encode production of a diffusible pigment and resistance to erythromycin and spectinomycin. The former was found occurring naturally in a clinical isolate of Staphylococcus aureus and the latter in S. epidermidis. Both plasmids are conjugative, capable of high-frequency, interspecies transfer, only isolated in the open-circular form and identical in molecular weight and pattern of restriction-endonuclease fragments. The only difference between the plasmids is in the expression of resistance, pWG4 encoding inducible and pWG25 constitutive erythromycin resistance. The resistance determinants of both plasmids behave as hitch-hiking transposons in cultural conditions that favour phage-mediated or phage-independent conjugation, always inserting a copy of themselves into the recipient's chromosome, except in S. epidermidis in which the chromosomal insertion site may be absent. The resistance determinants have been cloned and located on a 4 X 7 kbp EcoR1/HindIII restriction fragment which has a restriction map similar to that of the right arm of Tn554 (Murphy and Lofdahl, 1984). The hitch-hiking transposon of plasmid pWG25 has been designated Tn3853.

DNA Restriction Enzymes↗
PubMed1986

Isolation and characterisation of a family of small plasmids encoding resistance to nucleic acid-binding compounds in Staphylococcus aureus.

A family of small plasmids encoding resistance to nucleic acid-binding (NAB) compounds has recently been identified in strains of Staphylococcus aureus isolated in Italy, Texas and Western Australia. The mol. wts of the NAB-resistance plasmids are in the range (1.5-1.9) X 10(6) and all but one encode resistance to acridine yellow, ethidium bromide and quaternary ammonium compounds. The largest of the plasmids, pWG1773, differed in that it did not confer resistance to ethidium bromide. Restriction enzyme analysis of these plasmids revealed four distinct patterns corresponding to plasmids of four different mol. wts and physical maps were constructed based on the restriction patterns. Two plasmid types of molecular sizes approximately 2440 and 2240 base pairs had a 610-base pair region in common. Physical maps of the other two plasmid types were not related. The presence of a family of small NAB-resistance plasmids which carry no other known phenotypic markers provides further evidence for the strong selective advantage associated with maintenance of this determinant in clinical isolates of S. aureus.

Drug Resistance, Microbial↗
PubMed1986

Comparison of phage-mediated and conjugative transfer of staphylococcal plasmids in vitro and in vivo.

A strain of Staphylococcus aureus was constructed with which to compare transfer of resistance plasmids by the mechanisms of phage-mediated conjugation and conjugation. Transfer by each mechanism could be distinguished by the patterns of resistances transferred. Conjugation was favoured on dry absorbent surfaces, e.g., human skin, tissue and surgical gauze, whereas phage-mediated conjugation was favoured in fluids, e.g., milk and urine. The degree of hydration of the mating cells is postulated as one factor determining whether plasmids are transferred by phage-mediated conjugation or conjugation. Preliminary evidence indicates that topical creams and ointments affect the conjugative transfer of plasmids.

Anti-Bacterial Agents↗
PubMed1985

Genetics and epidemiology of methicillin-resistant Staphylococcus aureus isolated in a Western Australian hospital.

Strains of methicillin-resistant Staphylococcus aureus (MRSA) isolated in the Royal Perth Hospital (RPH) in Western Australia have been analysed genetically and three main types were characterized: (i) strains similar to those isolated in Europe before 1973. These strains caused small outbreaks in the RPH during the period 1966-1974, but have not been isolated in recent years, except from one patient with reactivation of osteomyelitis after 16 years; (ii) strains of the type prevalent in eastern and northern Australia, one of which caused a difficult-to-control outbreak in the RPH in 1982. Strains of this type have previously been isolated only from patients who had been in hospitals in eastern and northern Australia, but recently were isolated also from other patients--which indicates that this type of MRSA is now present in the Western Australian community; and (iii) strains, which are genetically different from either of the above two types, were isolated from patients who had been in hospitals in Southeast Asia, but have not yet caused an outbreak in the RPH.

Australia↗