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Biomedical subjects

L Harrison

Publications and source records attributed to L Harrison.

At least 73 records · Page 4Linked to original sources
PubMed1996

Low risk of perioperative infection without prophylactic antibiotics for transperineal prostate brachytherapy.

PURPOSE: To determine the incidence of postimplant infection in patients who are not given prophylactic antibiotics (ATBs). METHODS AND MATERIALS: One hundred thirty-one patients had computerized tomography (CT)-planned transperineal 125I implantation of the prostate from 1988 through 1995. One hundred fourteen of the patients did not receive prophylactic ATBs, 19 of whom required postimplant Foley catheter drainage for 1 day or more for acute urinary retention. RESULTS: The incidence of postimplant febrile episodes within 2 weeks of surgery among the patients who had not received prophylactic ATBs was 2 of 114 (2%). One of the two patients who developed postimplantation febrile episodes was treated successfully with ATBs as an outpatient. The second patient, who had a history of chronic lymphocytic leukemia (CLL) and immune suppression, developed E. coli sepsis and required intravenous antibiotics. Of 17 patients who received prophylactic ATBs, none had a postoperative febrile episode. CONCLUSION: We continue to refrain from routinely prescribing prophylactic ATBs unless there is some compelling circumstance including rheumatic heart disease, prosthetic devices, immune compromise, or a previous history of prostatitis.

Aged↗
PubMed1996

Reliability of the international normalized ratio for monitoring the induction phase of warfarin: comparison with the prothrombin time ratio.

The International Normalized Ratio (INR) was introduced to reduce the variability of prothrombin time (PT) reporting. One potential problem with the use of the INR is the assumption that its reliability is reduced when it is used to monitor patients during the induction phase of treatment. This shortcoming arises because the model used to establish the INR system is based on the use of pooled plasma from patients stabilized on warfarin for at least 6 weeks. Because the prolongation of the PT by warfarin during the induction phase mainly reflects reduction in factor VII levels (whereas the prolongation of the PT after 6 weeks of stabilization reflects reductions in factors X, II, and VII), there exists a potential for loss of accuracy of the INR during warfarin induction. To overcome this potential problem, it has been suggested that the PT ratio should be used to report results during the induction phase of treatment and that the INR system should be reserved for reporting results after the patient has been stabilized. This approach is confusing to the clinician. In addition, the validity of this approach has never been demonstrated in a clinical study. To address this issue, we studied 43 patients for the first 5 days after they started warfarin therapy. We measured the PT in the same plasma samples from each patient with five different commercial thromboplastins. The variance in the PT ratios among the five thromboplastins was compared with the variance obtained with the INR values derived from the PT ratios when using the international sensitivity indexes provided by the manufacturer. Our results indicate that, even during the induction phase, there is less variance with the INR system than with the PT ratio system.

Anticoagulants↗
PubMed1996

Regulated expression of APE apurinic endonuclease mRNA during wound healing in porcine epidermis.

Abasic (AP) sites in DNA are cytotoxic and mutagenic and their repair is initiated by AP endonucleases. The major AP endonuclease of mammalian cells is encoded by the APE gene. Ape protein has also been proposed to modulate the activity of some transcription factors independently of its AP endonuclease activity. We investigated whether APE expression is coordinated with cell division, which could diminish mutagenesis. The level of APE mRNA was followed during wound healing in porcine epidermis, in which surgical wounding prompts rapid cell proliferation followed by a differentiation program to regenerate normal skin. In situ hybridization with a probe from human APE cDNA revealed strongly decreased expression in rapidly proliferating migrating cells during the first 1-3 days following wounding, succeeded by sharply increased APE expression that exceeded the pre-wounding levels by days 9-17. These changes were not observed in the surrounding undamaged tissue. In contrast to the foregoing in vivo results, APE expression in cultured primary human fibroblasts (IMR90) or myeloid leukemia cells (K562) was not coordinated with cell division. This biphasic APE expression during wound healing could relate to transcription factor regulation or it could allow unhindered DNA synthesis or prepare the developing epidermis to handle DNA damage. However, if transient under-expression of APE-encoded repair enzyme does occur, it might render regenerating skin especially vulnerable to mutagenesis during the cell proliferation phase.

Animals↗
PubMed1996

Validation of catheter semiquantitative culture technique for nonstaphylococcal organisms.

The catheter semiquantitative culture roll tip technique has been validated as a discriminator between non-catheter-related bacteremias and catheter-related bacteremias (CRBs) caused by Staphylococcus species. However, this technique has not been specifically validated when used for the evaluation of catheters infected with organisms other than staphylococci. We reviewed catheters that had been submitted for semiquantitative roll tip culture as well as hospital records to determine clinical correlates of infection. Local infection and CRB were defined by standard criteria. Catheter-related sepsis (CRS) was defined as fever, leukocytosis, or hypotension which resolved with catheter removal, without another source of infection. For 195 catheters from 93 patients, gram-negative rods and enterococci were present on 36, fungi were on 25, Corynebacterium species were on 5, Bacillus species were on 3, Staphylococcus species were on 79, and 41 demonstrated no growth. Of 21 episodes of CRB or CRS due to nonstaphylococcal organisms, only 1 (questionable) episode was due to a catheter with < 15 CFU (P < 0.05). Eleven of these 21 episodes of CRB or CRS were due to gram-negative rods and enterococci, of which only the questionable episode was due to a catheter with < 15 CFU. Nine of these 21 episodes of CRB or CRS were due to fungi, none of which were associated with a catheter with < 15 CFU. The data for Staphylococcus species recapitulated published data (none of 21 CRB or CRS episodes were associated with catheters with < 15 CFU) and validated this retrospective technique. The data presented in this study validate the use of the semiquantitative culture technique for the evaluation of catheter-related infections caused by organisms other than staphylococci.

Bacteremia↗
PubMed1996

Tumor control and morbidity following transperineal iodine 125 implantation for stage T1/T2 prostatic carcinoma.

PURPOSE: To quantify disease progression and morbidity following computer tomography (CT)-based transperineal iodine 125 prostate implantation. METHODS: Ninety-two patients with clinical stage T1 or T2, Gleason score 2 to 7/10, prostatic carcinoma had outpatient, CT-based transperineal 125I prostate implantation and were monitored for 1 to 7 years (median, 3). The prescribed minimum radiation dose was 140 to 160 Gy. Lymph node dissection and postimplantation prostatic biopsies were not routinely performed. RESULTS: In 46% of patients, radiation-related urinary symptoms were substantial enough at 1 month following implantation to require medication. Radiation-related urinary symptoms gradually resolved. Two years after implantation, 14% of patients had persistent urinary symptoms of Radiation Therapy Oncology Group (RTOG) > or = grade 2. Eight percent of patients underwent a transurethral resection of the prostate (TURP) within 2 years of implantation. Five patients developed radiation-induced rectal ulcerations. Of 56 patients who were sexually potent preimplantation, 86% retained potency at 3 years. Twenty-five patients had biochemical disease progression. The overall actuarial freedom from biochemical failure rate at 4 years following implantation was 63%. In Cox proportional hazards multivariate analysis, the strongest predictor of failure was prostate-specific antigen (PSA) level less than or greater than 10 ng/mL (P = .005), followed by Gleason score (2 to 4 v 5 to 7, P = .08) and stage (T1 v T2, P = .09). CONCLUSION: The 5-year biochemical freedom-from-progression rates following transperineal 125I implantation are comparable with those achieved with prostatectomy. The morbidity has decreased with increased physician experience.

Aged↗
PubMed1996

Effects of gentle human touch on preterm infants: pilot study results.

A pilot study was conducted to evaluate the effects of gentle human touch (GHT) provided for 15 minutes a day to preterm infants from day 7 to day 12 of life. The study suggested that GHT has no adverse effects on the oxygen saturation or heart rate levels of small preterm infants and that GHT has a soothing effect as evidenced by decreased levels of active sleep, motor activity, and behavioral distress. These results can provide NICU nurses with a basis for guiding parents in their early interactions with preterm infants in the NICU.

Female↗
PubMed1995

Dosimetry guidelines to minimize urethral and rectal morbidity following transperineal I-125 prostate brachytherapy.

PURPOSE: To establish dosimetry guidelines to minimize urethral and rectal morbidity following permanent I-125 prostatic brachytherapy. METHODS AND MATERIALS: Dosimetric parameters were correlated with long-term morbidity for 65 patients following transperineal I-125 implantation for Stage T1/T2 prostatic carcinoma. The prescribed minimum prostatic dose was 150 Gy. The median total activity used was 48 mCi (range: 32-77 mCi). Patients were followed for 1-5 years (median follow-up: 2 years). Postimplant computerized tomography (CT)-based dosimetry was performed for 45 patients. Morbidity was evaluated using a modification of the RTOG grading system, with a scale of grade 0-5. RESULTS: The incidence of grades 2 and 3 urinary morbidity was associated with the maximum central urethral dose (p = 0.03), and with the length of urethra that received greater than 400 Gy (p = 0.07). Patients with larger prostates had more long-term urinary morbidity (p = 0.06). Rectal bleeding (RTOG grade 1) or ulceration (RTOG grade 2) was associated with irradiation of the rectal wall to doses in excess of 100 Gy (p = 0.02). There was no relationship between the matched peripheral dose (MPD), mCi/source or total mCi implanted and long-term morbidity. CONCLUSIONS: Postimplant, CT-based dosimetry can predict which patients are at higher risk of radiation-related morbidity. More simplistic parameters including the MPD, total activity implanted, or mCi/source, had no relationship with morbidity. To decrease the risk of long-term morbidity, an effort should be made to keep the central urethral dose below 400 Gy, and the rectal surface dose below 100 Gy.

Brachytherapy↗
PubMed1995

Characterization of the promoter region of the human apurinic endonuclease gene (APE).

Apurinic/apyrimidinic (AP) sites are mutagenic and block DNA synthesis in vitro. Repair of AP sites is initiated by AP endonucleases that cleave just 5' to the damage. We linked a 4.1-kilobase pair HindIII DNA fragment from the region upstream of the human AP endonuclease gene (APE) to the chloramphenicol acetyltransferase (CAT) gene. Deletions generated constructs containing 1.9 kilobase pairs to 50 base pairs (bp) of the APE upstream region. Transient transfection studies in HeLa cells established that the basal APE promoter is contained within a 500-bp fragment. The major transcriptional start site in HeLa, hepatoma (HepG2), and myeloid leukemic (K562) cells was mapped to a cluster of sites approximately 130 bp downstream of a putative "CCAAT box," approximately 130 bp 5' of the first splice junction in APE. Deletion of 5' sequences to within 10 bp of the CCAAT box reduced the CAT activity by only about half, and removal of the CCAAT box region left a residual promotor activity approximately 9%. Deletion to 31 bp upstream of the transcriptional start site abolished APE promoter activity. DNA sequence analysis revealed potential transcription factor recognition sites in the APE promoter. Gel mobility-shift assays showed that both human upstream factor and Sp1 can bind their respective sites in the APE promoter. However, DNase I footprinting using HeLa nuclear extract showed that the binding of Sp1 and upstream factor is blocked by the binding of other proteins to the nearby CCAAT box region.

Animals↗
PubMed1994

Short-term freedom from disease progression after I-125 prostate implantation.

PURPOSE: To evaluate short-term clinical and chemical disease progression following computed tomography (CT)-based transperineal I-125 prostate implantation. METHODS AND MATERIALS: Sixty-two patients with clinical Stage T1 or T2 prostatic carcinoma had outpatient, CT-based transperineal I-125 prostate implantation and have been followed for 6-55 months (median: 19 months). Fifty-six patients had an elevated prostate specific antigen (PSA) before implantation (> 4.0 ng/mL). Twenty patients had well-differentiated tumors, 39 were moderately differentiated, 2 were poorly differentiated, and 1 was indeterminate. A total of 32-73 mCi I-125 was implanted (median: 47 mCi). The prescribed minimum prostatic dose was 140-160 Gy, and the actual matched peripheral dose ranged from 109-258 Gy (median: 160 Gy). Lymph node dissection or postimplantation prostatic biopsies were not routinely performed. RESULTS: Of 54 patients with an elevated PSA prior to implantation and no prior hormonal treatment, 96% returned to normal within 24 months of treatment. In 85% of patients, the PSA fell below 2.0 ng/mL and in 74% of patients, the PSA value fell to below 1.0 ng/mL. Seven patients had disease progression, one of whom has an isolated, rising PSA. The actuarial rate of chemical (rising PSA) or clinical failure at 3 years following implantation was 17%. Of 38 patients who were sexually potent prior to implantation, 81% remained potent at 3 years. Five patients developed radiation-induced rectal ulcerations, 11-22 months following implantation. Three patients required a transurethral resection of the prostate for postimplant urinary symptoms. CONCLUSIONS: The short-term clinical and chemical freedom-from-progression rates following I-125 implantation are comparable to that achieved with prostatectomy, with high preservation of sexual potency and moderate morbidity.

Aged↗
PubMed1994

Fluoroscopic visualization of the prostatic urethra to guide transperineal prostate implantation.

PURPOSE: To describe a novel way to assure proper needle positioning within the prostate during transperineal implantation, using the urethra as the primary radiographic landmark. METHODS AND MATERIALS: Preoperative computerized tomography (CT) images through the prostate are used to plan optimal transperineal needle-seed placement. When performing the procedure, a Foley catheter, with radio-opaque wire is used to visualize the prostatic urethra fluoroscopically in anterior-posterior and lateral projections. Proper needle placement is determined by their position relative to the urethra. RESULTS: Sixty patients have been implanted with this method at Memorial Sloan-Kettering Cancer Center from 1990-1992. CONCLUSION: The method described here is an improvement over previously described CT-based techniques. It could be used to supplement or replace ultrasound imaging.

Brachytherapy↗
PubMed1994

Treatment-related symptoms during the first year following transperineal 125I prostate implantation.

PURPOSE: To summarize the urinary, rectal, and sexual symptoms occurring during the first 12 months following 125I prostatic implantation. METHODS AND MATERIALS: Thirty-one patients with Stage T1 or T2 prostatic carcinoma were evaluated for morbidity following computed tomography-guided transperineal 125I implants from 1988 to 1991. The median total activity used was 47 mCi (range 35-73 mCi). Toxicity was evaluated using a modification of the Radiation Therapy Oncology Group grading system. RESULTS: Nocturia was the most common treatment-related symptom, reported by 80% of patients within 2 months after implantation, and persisted at 12 months in 45% of the patients. Mild dysuria developed in 48% of patients within 2 months of implantation; two patients needed analgesics for their dysuria. Terazosin hydrochloride (2-10 mg qd) provided subjective improvement of urinary symptoms in seven of eight patients in whom it was tried. Rectal urgency, soft stools, and increased frequency of bowel movements was reported by 25% of the patients within 1-2 months after implantation. The incidence of asymptomatic rectal bleeding or ulceration occurring at any time after implantation was 47%, but resolved in all patients with expectant treatment. Self-limited ulceration of the rectal mucosal occurred in 16%, but only one patient developed a prostato-rectal fistula, managed with an ileal conduit. Five of the 18 potent patients experienced discomfort on erection or ejaculation, beginning within several weeks of their implant. The discomfort resolved within 6 months in three of the patients, but persisted for 18 and 24 months in the other two. CONCLUSION: 125I implantation, as performed in this series, is generally associated with only mild-moderate genitourinary and rectal symptoms that may persist 6 months or more after implantation. Prostatic carcinoma, Brachytherapy, Morbidity.

Aged↗
PubMed1994

Cisplatin, fluorouracil, and leucovorin. Increased toxicity without improved response in squamous cell head and neck cancer.

OBJECTIVE: To evaluate the activity and toxicity of the drug combination cisplatin, fluorouracil by continuous infusion, and high-dose oral leucovorin calcium (PFL) as induction chemotherapy in patients with advanced and untreated squamous cell head and neck (SCHN) cancer. DESIGN: Nonrandomized, prospective trial. SETTING: Referral center (comprehensive cancer center). PATIENTS: Twenty-two patients with stage III (n = 7) and IV (n = 15) M0 SCHN cancer of the larynx (n = 13), hypopharynx (n = 7), and oropharynx (n = 2) whose standard treatment would have required total laryngectomy. INTERVENTIONS: Three cycles of PFL were administered prior to local-regional therapy (concomitant cisplatin and radiation and/or neck dissection, with total laryngectomy reserved for nonresponse or relapse). Chemotherapy included cisplatin (100 mg/m2) on day 1 by short intravenous infusion; fluorouracil (800 mg/m2) on days 1 through 5 by continuous infusion; and leucovorin (100 mg) every 4 hours by mouth for 30 doses. The PFL combination was administered every 21 days. MAIN OUTCOME MEASURES: Clinical response to chemotherapy and observed toxic effects during chemotherapy. RESULTS: Five patients were inevaluable for response, with three early deaths (infection in two and sudden death in one), one cerebrovascular accident, and one patient declining further chemotherapy. Of the remaining 17 patients, 10 had a major response to chemotherapy, but in only five patients (29%) was this complete (95% confidence interval, 8% to 51%). Other significant toxic effects included grade 3 to 4 mucositis in eight patients and grade 3 to 4 neutropenia in 10. CONCLUSIONS: While PFL is active in patients with SCHN cancer, we were unable to reproduce the high complete response rates reported by other centers. Its use can be associated with significant toxic effects. We do not recommend the use of PFL for the treatment of patients with SCHN cancer outside the context of a clinical trial until there is further critical assessment of its activity and toxicity.

Adult↗
PubMed1994

New perspectives on rheumatoid arthritis.

Rheumatoid arthritis (RA) remains one of the most common, puzzling and poorly treated diseases of humans. However, a surge of interest in the biology of chronic inflammation and in the design of more-potent and specific inhibitors of pro-inflammatory pathways heralds an optimistic era for the treatment of RA. A recent symposium provided a multidisciplinary perspective on the current status of such studies.

Arthritis, Rheumatoid↗
PubMed1994

Restoring a failed prefabricated post and core with a sleeve casting: a clinical report.

A clinical case is described, and a technique is explained for making a custom sleeve cast post and core to salvage a fractured crown previously treated with an unretrievable prefabricated post. The restorative problem was to design and fabricate some sort of cast post and core that could be cemented to the remaining post. The amalgam and cement in the pulp chamber and coronal portion of the root canal were carefully removed so that a direct pattern could be made to form a tube which would surround the coronal part of the existing post like a sleeve. This sleeve casting was designed to provide attachment for a core to support a new restoration. This direct pattern technique results in a retained core that joins the already cemented post and provides a sound core for the retention of a new crown.

Crowns↗
PubMed1994

A technique for developing a master cast with previously made dies.

This article describes a technique for preparing final working casts to be used in the laboratory phase of restorative treatment. The goal is to produce accurate working casts that have stable dies which are easily removed from the base and reliably replaced. Most casts with removable dies are made from a single master impression. However, individual dies are sometimes made previously from individual tooth (preparation) impressions. In such cases, transfer copings are required to relate the dies and produce the final working cast. Hollow plastic casting sprues are used as temporary dowels in this technique until a transfer coping pickup impression has been made. After the dies are seated and secured in the transfer coping pickup impression, the plastic casting sprues are replaced with conventional brass dowel pins. This technique ensures well-placed dowel pins that will facilitate easy and accurate withdrawal and replacement of the dies.

Dental Casting Technique↗