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Biomedical subjects

E Johnston

Publications and source records attributed to E Johnston.

At least 19 recordsLinked to original sources
PubMed2004

Histological changes in radial forearm skin flaps in the oral cavity.

We reported previously that skin flaps transplanted to the oral cavity in reconstructive surgery for oral cancer frequently acquired the gross appearance of buccal mucosa. The changes were shown to be reactive in nature. The "changed" flaps generally had a heavier infiltration of leukocytes in the dermis and appeared to have thicker epithelium. The present study quantifies these parameters, as well as the numbers of intraepithelial leukocytes. The flaps that had acquired the gross appearance of oral mucosa had significantly thicker epithelium, larger numbers of dermal leukocytes, and more intraepidermal inflammatory cells per unit length than flaps that retained the gross appearance of thin skin. No correlation was found between these changes and radiotherapy.

Adult↗
PubMed2004

Power of exclusion for parentage verification and probability of match for identity in American Kennel Club breeds using 17 canine microsatellite markers.

DNA analysis of microsatellite markers has become a common tool for verifying parentage in breed registries and identifying individual animals that are linked to a database or owner. Panels of markers have been developed in canines, but their utility across and within a wide range of breeds has not been reported. The American Kennel Club (AKC) authorized a study to determine the power to exclude non-parents and identify individuals using DNA genotypes of 17 microsatellite markers in two panels. Cheek swab samples were voluntarily collected at Parent Breed Club National Specialty dog shows and 9561 samples representing 108 breeds were collected, averaging 88.5 dogs per breed. The primary panel of 10 markers exceeded 99% power of exclusion for canine parentage verification of 61% of the breeds. In combination with the secondary panel of seven markers, 100% of the tested breeds exceeded 99% power of exclusion. The minimum probability match rate of the first panel was 3.6 x 10(-5) averaged across breeds, and with the addition of the second panel, the probability match rate was 3.2 x 10(-8); thus the probability of another random, unrelated dog with the same genotype is very low. The results of this analysis indicated that, on average, the primary panel meets the AKC's needs for routine parentage testing, but that a combination of 10-15 genetic markers from the two panels could yield a universal canine panel with enhanced processing efficiency, reliability and informativeness.

Animals↗
PubMed2004

[Descompresive craniectomy in head injury. Intractable I.C.P. ].

Decompressive craniotomy is a neurosurical technique known since the origin of neurosurgery, but its use as a routine started at the end of the 19th century. In last decades, the use of decompressive craniotomy decreased, mainly because of poor results obtained and the advances in medical treatment of refractory intracranial hypertension in the Intensive Care Units. Nevertheless, in recent years there has been a renewed interest with the use of this surgical techique in young patients with head injuries and severe intracranial hypertensio'n, but no surgical mass lesion, as well as in patients with ischemic stroke causing life threatening mass effect. The authors present a series of four young patients with head injuries and "malignant" intracranial hypertension on whom wide craniotomies were performed with an excellent outcome. The literature is reviewed.

Adult↗
PubMed2003

Surgical treatment of intracranial hypertension in encephalic cryptococcosis.

The incidence of cryptococcosis has risen sharply together with the growing number of patients with Acquired Immunodeficiency Syndrome (AIDS). Cryptococcal meningitis is nowadays the most common intracranial non-viral infection in such cases. One of its most serious complications is intracranial hypertension (ICH), a situation that can lead either to early death, or disabling sequelae. The authors analyse a series of 10 cases of encephalic cryptococcosis with ICH, and describe the clinical course, diagnosis, medical and surgical treatment, and evolution. The physiopathology of ICH in these patients is discussed, proposing placement of a ventriculo-peritoneal shunt as the primary and emergency treatment, even when ventricular enlargement might be absent. Although the present series is certainly small, from the preceding discussion and according to an extensive bibliographical review, our conclusion is that patients with encephalic cryptococcosis and uncontrollable ICH should receive surgical treatment, consisting of an emergency diversion of the CSF, because serial lumbar punctures are not enough to improve the clinical course, that if left to its natural evolution would lead to a fatal outcome in a short time. In spite of the fact that CSF shunts were carried out on immunocompromised patients, no superinfections occurred.

AIDS-Related Opportunistic Infections↗
PubMed2000

Prenatal transmission of subtype C HIV-1 in Zimbabwe: HIV-1 RNA and DNA in maternal and cord blood.

Maternal and cord samples from HIV-seropositive women and their infants in Zimbabwe, where subtype C is the predominant strain of HIV, were analyzed to determine the frequency of detection of HIV RNA and DNA. HIV RNA was detected in 90% of maternal and in 38% of cord plasma at levels at least 25% of maternal plasma. Heteroduplex mobility assays and sequencing of virus envelope (C2-V5) demonstrated closely related, but unique, subtype C viruses in maternal and cord RNA, and a significantly greater frequency of cord viremia among women with homogenous, compared with heterogeneous viral envelope RNA. Quantification of RNA, measures of envelope viral diversity, and phylogenetic analysis of maternal and cord plasma RNA provide evidence for the frequent exposure and potential transmission of HIV from mother to infant before birth.

Adult↗
PubMed2000

Randomized, dose-escalation study of SD/01 compared with daily filgrastim in patients receiving chemotherapy.

PURPOSE: To explore the use of SD/01 (a polyethylene glycol-conjugated filgrastim shown in preclinical studies to have a prolonged half-life) in patients with chemotherapy-induced neutropenia. PATIENTS AND METHODS: Thirteen patients with non-small-cell lung cancer were randomized to receive daily filgrastim (5 microg/kg/d) or a single injection of SD/01 (30, 100, or 300 microg/kg) 2 weeks before chemotherapy and again 24 hours after administration of carboplatin and paclitaxel. Pharmacodynamic, pharmacokinetic, and safety analyses were performed. RESULTS: Peak serum concentrations of SD/01 and the duration of increased serum concentrations were dependent on the SD/01 dose. SD/01 concentrations remained increased longer in patients with chemotherapy-induced neutropenia. Prechemotherapy median absolute neutrophil counts (ANCs) in patients receiving SD/01 were increased in a dose-dependent fashion, with the duration of this effect also being dose dependent. After chemotherapy, median ANC nadirs were similar in the filgrastim cohort and the cohort receiving SD/01 30 microg/kg, with higher nadirs seen in the cohorts receiving SD/01 100 or 300 microg/kg. Dose-limiting toxicities were not noted. CD34(+) cells were mobilized in all cohorts. CONCLUSION: A single dose of SD/01 increases the serum concentration of SD/01 for several days in a dose-dependent fashion and is not associated with significant toxicity. The effects of SD/01 on ANC and CD34(+) cell mobilization are comparable or greater than those achieved with daily filgrastim. The self-regulation of this molecule provides a potential therapeutic advantage in a variety of clinical settings associated with neutropenia.

Aged↗
PubMed1999

Removal of a PCR inhibitor and resolution of DNA STR types in mixed human-canine stains from a five year old case.

The analysis of biological trace evidence from a reopened investigation into a 1991 murder from Vernon, B.C. revealed mixed human and dog bloodstains on blue jean pants that contained a PCR inhibitory substance. The presence of the inhibitory substance was detected by the inhibition caused from adding a small aliquot of the test DNA extract into a PCR reaction designed to produce a known standard product. The removal of the PCR inhibitory substance was accomplished by treating the extracted DNA with Thiopropyl Sepharose 6B beads. DNA profiles from two human contributors and a canine were obtained using species specific polymorphic STR markers. The two human DNA profiles obtained from blue jean pants were resolved, one matched the suspect and the other matched the victim. The DNA profile from the canine component matched that obtained from the known sample of the victim's dog who was also slain during the assault. This evidence along with other DNA typing evidence was critical in obtaining a resolution of the case.

Aged↗
PubMed1998

Insulin lispro: a fast-acting insulin analog.

Research has established the importance of maintaining blood glucose levels near normal in patients with type 1 (insulin-dependent) diabetes mellitus. Short-acting insulin analogs are designed to overcome the limitations of regular short-acting insulins. Compared with regular human insulin, the analog insulin lispro offers faster subcutaneous absorption, an earlier and greater insulin peak and a more rapid postpeak decrease. Insulin lispro begins to exert its effects within 15 minutes of subcutaneous administration, and peak levels occur 30 to 90 minutes after administration. Duration of activity is less than five hours. Rates of insulin allergy, lipodystrophy, hypoglycemia and abnormal laboratory test results are essentially the same in patients using insulin lispro and in those using regular human insulin.

Blood Glucose↗
PubMed1998

Bcl-2 oncoprotein positivity and high MIB-1 (Ki-67) proliferative rate are independent predictive markers for recurrence in prostate carcinoma.

Predicting the clinical behavior of prostate carcinoma can be difficult; one approach is to identify molecular prognostic markers. We evaluated proliferative rate (MIB-1 antibody) and expression of bcl-2, p53, and retinoblastoma (pRB) proteins, which have cell cycle-related functions, in 208 consecutive radical prostatectomy specimens. Values were correlated with histopathologic parameters (Gleason tumor score, tumor amount, capsule invasion, and involvement of surgical margins, seminal vesicles, or lymph nodes) and with recurrence-free survival (4-year median follow-up). A high MIB-1 proliferative rate was associated with all of the measured histopathologic parameters, p53 overexpression with tumor amount, and pRB expression with positive lymph nodes. pRB and p53 expression levels were not associated with differences in recurrence-free survival. A high MIB-1 proliferative rate and bcl-2 positivity were associated with increased recurrence, both considered individually, and also independently and additively when examined together and with the most predictive histopathologic factors (Gleason tumor score and seminal vesicle involvement). MIB-1 proliferative rate and bcl-2 positivity may prove to be useful markers for poor prognosis in prostate carcinoma.

Biomarkers, Tumor↗
PubMed1997

Chronic disorders of the Achilles tendon: results of conservative and surgical treatments.

We reviewed our results of nonoperative and operative treatment of chronic Achilles tenosynovitis to further define outcomes and treatment parameters. Forty-one patients presented with an average of 14 weeks of Achilles tendon symptoms. All patients received nonsurgical treatment initially, and 21 patients (51%) recovered after an average of 18 weeks of therapy. Three additional patients improved after brisement of the tendon/peritenon interspace. Seventeen of 41 patients eventually underwent soft tissue tenolysis and/or excision of degenerative tendon cysts. Those patients who responded to nonoperative therapy tended to be younger (average age, 33 years) than those who had degenerative tendon changes requiring surgery (average age, 48 years). All surgical patients were able to return to unrestricted activity after 31 weeks (range, 27-48 weeks). We believe 4 to 6 months of nonsurgical therapy is appropriate for middle aged patients or athletes with chronic Achilles tenosynovitis. Those that fail this treatment will improve with a limited debridement of diseased tissue without excessive soft tissue dissection of the tendon.

Achilles Tendon↗
PubMed1997

Care of adolescent girls.

Primary care of girls between the ages of 10 and 20 presents some unique challenges. This article presents a review of normal adolescent development and explores preventive health issues and some of the more common acute medical problems of adolescent girls. Counseling on some behavioral and psychosocial issues also is discussed. Finally, anticipatory guidance topics to be discussed with parents are included.

Acute Disease↗
PubMed1995

High dose rate endobronchial brachytherapy in the management of primary and recurrent bronchogenic malignancies.

BACKGROUND: The clinical, radiographic, and bronchoscopic records of patients treated with out-patient high dose rate (HDR) endobronchial brachytherapy were reviewed to determine its effectiveness in patients with malignant airway obstruction (with or without prior external beam radiation). In addition, quality of life and acute and chronic morbidity were evaluated. METHODS: From January 1, 1989 to June 30, 1993, 46 patients received 128 HDR endobronchial treatments employing a high activity Ir-192 source with a remote afterloader. Patients treated had a total of 22 primary and 17 recurrent bronchogenic carcinomas, 7 of which were metastatic nonpulmonary tumors. Three separate fractions of 7.0 Gy were prescribed to a depth of 1.0 cm. and given 1 week apart. Twelve patients (30%) received prior external beam irradiation (median dose, 58 Gy). RESULTS: Median follow-up for the entire group was 5 months (17.5 for surviving patients). Of the eight asymptomatic patients, five (62%) remained asymptomatic for the remainder of their lives. Of the 38 symptomatic patients, 28 (74%) had significant clinical improvement, and 12 of them remained improved for the duration of their lives. Of thirty-six (78%) patients examined for radiographic response, 25 (69%) had a partial or complete response to this treatment. In patients without prior irradiation, there was a tendency for a higher percentage of clinical and radiographic response. Two patients (4%) experienced mild, transient dysphagia, four patients developed self-limited radiation pneumonitis (9%), and three patients (7%) suffered fatal hemoptysis (all of these patients received prior or concurrent external beam radiotherapy). No factor (i.e., prior radiation therapy, number of catheters placed, surgery, or chemotherapy) predicted an increased risk of complications (P = NS). CONCLUSIONS: Outpatient HDR endobronchial brachytherapy is effective in both preventing and relieving endobronchial obstruction in patients with or without prior irradiation, recurrent lesions, or metastatic nonpulmonary disease. A significant proportion of patients can be rendered asymptomatic for the duration of their lives, hence were provided with improved quality of life. These treatments are well tolerated and safe, and result in minimal long term morbidity.

Aged↗
PubMed1994

Quantitative vibrometry and electrophysiological assessment in screening for carpal tunnel syndrome among industrial workers: a comparison.

Vibrometry has been demonstrated to be an effective adjunct to electrophysiological evaluation of nerve integrity in diffuse peripheral neuropathies but there is controversy over its value in the diagnosis of isolated compression neuropathy such as carpal tunnel syndrome (CTS). One hundred thirty factory workers were screened for peripheral nerve impairment using both vibrometry and electrophysiologic testing of digits 2 and 5 in both hands. Vibrometry had a low sensitivity in identifying individuals with symptoms of CTS or a median mononeuropathy defined by nerve conduction studies (NCS). The correlation of vibratory and the sensory evoked latencies were modest in the median nerve distribution (r = 0.297 to 0.370, p = 0.001). Using a comparison between vibration thresholds from digit 2 to 5 was not helpful in identifying cases of CTS and the difference in thresholds did not correlate with the difference in sensory evoked latencies. CTS is primarily a demyelinating process and can be easily detected with NCS. Because vibration threshold sensation is related to axonal loss it is not as sensitive in early CTS. Our results do not support the use of quantitative vibrometry as a screening tool median nerve impairment among industrial workers.

Adult↗
PubMed1994

Evaluation of current perception threshold testing as a screening procedure for carpal tunnel syndrome among industrial workers.

Eighty-four workers participated in a work-site screening program designed, in part, to estimate the prevalence of carpal tunnel syndrome (CTS). Each worker completed a discomfort survey, limited electrodiagnostic testing of the median and ulnar sensory nerves in each wrist, and current perception threshold (CPT) testing in the right 2nd digit using the NEUROMETER CPT device. A subset of study participants also completed CPT testing in digit 5 on the right (n = 33). Comparisons were made among the CPT results, symptoms consistent with CTS, and electrophysiologic findings. The CPT results correlated poorly with electrophysiologic parameters from the same nerve distribution, and CPT results were statistically unrelated to self-reported symptoms that may be suggestive of CTS. The test performance characteristics of CPT testing (sensitivity, specificity, positive predictive value, and negative predictive value) were low in comparison with electrodiagnostic measurements and self-reported symptoms consistent with CTS. The electrophysiologic results were significantly associated with the constellation of symptoms that are consistent with CTS. On the basis of these results, CPT testing cannot be recommended as a screening procedure for identification of possible cases of CTS among active industrial workers.

Adult↗
PubMed1993

A spectroscopic investigation of losartan polymorphs.

Losartan, an antihypertensive agent in clinical development, was found to exist in two enantiotropic polymorphic forms, a low-temperature stable form (Form I) and a high-temperature stable form (Form II), the temperatures at which they are stable being related to the transition temperature. X-ray powder diffraction patterns indicated differences in the crystal packing of the two forms. The vibrational data from infrared and Raman spectroscopy suggested a subtle change in molecular conformation and crystal packing in the two forms. Solid-state 13C NMR data of the polymorphs concurred with the vibrational data and indicated that, while the observed line widths reflect no major changes in crystallinity, signal multiplicities and chemical shifts do reflect differences in molecular packing in the respective unit cells. Thus, in the absence of crystallographic data, useful structural information could be derived from spectroscopic results to identify each of the crystalline forms.

Antihypertensive Agents↗
PubMed1992

[Intracranial hemorrhage in hemophiliacs. Study of 10 episodes].

The intracranial haemorrhages presented within a group of 64 haemophiliacs along 25 years were revised. During this period, 10 such episodes were seen in 8 patients with haemophilia A; six of them appeared in children under 10 years of age. In five instances there were traumatic antecedents, whereas in the remaining five the haemorrhage was spontaneous, no vascular abnormalities being demonstrated in these last. The lesions observed were: intracerebral haematoma in three instances, subdural haematoma in four, subarachnoid haemorrhage in two cases and cerebellar haematoma in one case. Only one of the episodes was lethal, death being related with infectious complications. Recurrences were observed in two patients. Two patients had sequelae with seizures, plus mental retardation and motor deficit in one of them. Substitutive therapy shows capable of controlling this severe complication of haemophilia, provided it is started promptly and fair rates of factor VIII are maintained. Such therapy must be kept for longer periods in these patients with traumatic antecedents.

Adolescent↗
PubMed1991

Attitudes of a group of South African speech and hearing therapists towards patients with acquired immunodeficiency syndrome (AIDS).

The present study investigated the attitudes, knowledge and fears of a group of 31 speech-language pathologists and audiologists working in 13 hospital settings, concerning patients with AIDS/HIV. Individuals completed an anonymous, self-administered questionnaire assessing self-perceived level of knowledge, actual knowledge of modes of transmission of the AIDS virus and protection procedures, and attitudes and fears associated with treatment of AIDS/HIV patients. Qualitative data concerning responses to this epidemic were also obtained and statistical analyses were completed to determine the relationship between the above mentioned variables. Results indicate that the higher the respondents' level of actual knowledge, the more they reportedly feared the disease. No correlation was found between respondents' level of actual knowledge and their attitudes. Information needs were identified which have important implications for future education. In addition, proposed policy guidelines for speech-language pathologists and audiologists in contact with AIDS/HIV patients, based on the above results of the study are provided.

Acquired Immunodeficiency Syndrome↗