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Biomedical subjects

W Ellis

Publications and source records attributed to W Ellis.

At least 37 records · Page 2Linked to original sources
PubMed1997

Cluster of wound botulism in California: clinical, electrophysiologic, and pathologic study.

Over a period of 15 months we have seen 6 patients with long-standing history of subcutaneous heroin injections who experienced acute blurred vision, dysphagia, dysarthria, and generalized weakness. Decreased or absent deep tendon reflexes, pupillary abnormalities, incremental responses to fast repetitive nerve stimulation, and positive serology for Clostridia botulinum toxin A were found, but not in all cases. Muscle biopsies showed variable signs of neurogenic atrophy. In vitro electrophysiology studies revealed decreased end-plate potentials quantal content, confirming the presynaptic nature of the disorder. Mechanical ventilation was required in 5 patients. Half of the patients were treated with polyvalent antitoxiin. Prognosis was favorable, though recovery was slow. In conclusion, acute bulbar weakness with visual symptoms in patients with subcutaneous heroin abuse strongly suggets the possibility of wound botulism. High diagnostic suspicion combined with histology and in vitro electrophysiology confirmation of presynaptic failure, especially in seronegative cases, may significantly improve morbidity.

Adult↗
PubMed1996

Intermittent androgen suppression with leuprolide and flutamide for prostate cancer: a pilot study.

OBJECTIVES: To affirm the feasibility of using intermittent androgen suppression in patients with hormone-naive prostate cancer. METHODS: Leuprolide and flutamide were administered for 9 to 12 months and then discontinued until prostate-specific antigen (PSA) levels reached a threshold value determined by the baseline PSA value. This constituted one cycle of treatment. Androgen suppression was then administered intermittently as described until there was evidence of androgen independence. RESULTS: Twenty-two patients with PSA failure after primary therapy with surgery and/or radiation and untreated early or Stage D2 disease were treated. Twenty-one patients completed androgen suppression during cycle 1, with a median time to PSA nadir of 3.5 months (range, 2 to 12). Fifteen patients completed cycle 1 with a median time off treatment of 6 months (range, 2 to 19) or 38% (range, 17% to 64%) of a treatment cycle. Six patients continued off treatment during cycle 1 for 1+ to 31+ months. During cycle 2, 12 patients achieved a PSA nadir in a median time of 3.5 months. Two patients completed cycle 2 with a median time off treatment of 10 months (51%). Median follow-up for all patients is 26 months (range, 10 to 51). While off treatment, all patients reported a reduction of symptoms associated with androgen suppression. CONCLUSIONS: Intermittent androgen suppression is a feasible alternative to continuous androgen suppression for treatment of prostate cancer, and quality of life is improved while off treatment.

Aged↗
PubMed1995

Activity of azithromycin as a blood schizonticide against rodent and human plasmodia in vivo.

We compared the efficacy of azithromycin to the clinical antimalarial doxycycline in Plasmodium berghei-infected mice and in P. falciparum-infected Aotus monkeys. When mice were administered drug orally twice a day for three days, the minimum total dose of azithromycin that cured all mice was 768 mg/kg. Doxycycline at a dose of 1,536 mg/kg cured no mice. The efficacy of fast-acting blood schizonticides (quinine, halofantrine, artemisinin) against P. berghei was augmented by azithromycin. In monkey experiments in which there were two animals per experimental group, azithromycin (100 mg/kg/day for seven days) eliminated parasitemia; azithromycin (30 mg/kg/day) initially cleared 99.8-100% of the parasites with recrudescence in the one completely cleared case. Doxycycline (30 mg/kg/day) cleared 100% of the parasites with recrudescence in both cleared cases. Since azithromycin can be clinically administered at a somewhat higher daily dosage than doxycycline, the data suggest that it may be possible to replace drugs of the tetracycline class with azithromycin in combination with fast-acting blood schizonticides for the treatment of P. falciparum infection.

Administration, Oral↗
PubMed1995

Androgen-induced changes in electrocommunicatory behavior are correlated with changes in substance P-like immunoreactivity in the brain of the electric fish Apteronotus leptorhynchus.

The hormonal regulation of sex differences in electrocommunicatory behavior and brain substance P-like immunoreactivity (SPI-ir) were examined in the weakly electric fish, Apteronotus leptorhynchus. This animal modulates its electric organ discharge (EOD) to produce discrete electric social signals (chirps), which function in aggressive and reproductive displays. Males readily chirp in response to electrosensory stimuli that mimic the presence of a conspecific; females also chirp in response to such stimuli, but do so at much lower rates than males. We have recently demonstrated that androgen treatment enhances chirping behavior in females and may also lead to a change in chirp quality or structure. In this study, we quantified androgen-induced changes in chirp structure and simultaneously examined whether androgens alter the sexually dimorphic pattern of SPI-ir in a brain region (prepacemaker nucleus, PPn) known to control chirping. Our results demonstrate that, in females, androgens cause both the induction of chirping and an alteration of chirp structure; chirps recorded from androgen-implanted females had longer durations and more dramatic frequency and amplitude modulations compared to controls, and appear similar to those reported to be produced during spawning. Moreover, androgen-induced changes in chirping are correlated with increased expression of SPI-ir within specific brain nuclei of females. These changes may underly behavioral changes in chirping, since treated females showed a male-like pattern of SPI-ir in the PPn. However, alterations in SPI-ir were not restricted to the PPn, but also occurred in diencephalic regions related to pituitary function and reproductive behavior. The results suggest that androgens modulate chirping activity and cause both specific and wide-spread changes in SPI-ir that may relate to a functional system that interrelates pituitary function, reproductive behavior, and chirping.

Androgens↗
PubMed1995

The influence of volumetric tumor doubling time, DNA ploidy, and histologic grade on the survival of patients with intracranial astrocytomas.

PURPOSE: To improve the prediction of individual survival in patients with intracranial astrocytomas through the analysis of volumetric tumor doubling time (VDt) and DNA ploidy. METHODS: A pilot study was retrospectively conducted on a group of 25 patients with intracranial astrocytomas in whom recurrent and/or progressive disease was observed on serial contrast-enhanced CT or MR examinations. VDt was computed using two or more data points from a semilogarithmic plot of tumor volume versus time. Size-adjusted survival was calculated using a method based on VDt and initial tumor volume to decrease the lead time bias attributable to differing tumor sizes at presentation. RESULTS: Slower VDt was associated with significantly longer survival and size-adjusted survival as determined by a univariate Cox proportional hazard analysis. Aneuploidy was a significant indicator of poor survival. Aneuploid and multiclonal astrocytomas had poor size-adjusted survivals compared with diploid astrocytomas. Grade IV astrocytomas had significantly poorer survival and size-adjusted survival compared with lower grades (I to III), which individually were not significantly correlated. However, grade IV histology was not a significant independent predictor of size-adjusted survival in a multivariate Cox model, whereas VDt and DNA ploidy remained significant. VDt also had a significant direct linear correlation to survival and size-adjusted survival. CONCLUSIONS: VDt and DNA ploidy were more sensitive than histologic grading as indicators of individual survival. Initial tumor size needs to be considered when staging and assessing survival in patients with intracranial astrocytomas.

Adolescent↗
PubMed1994

Antimalarial activity of WR 243251, a Dihydroacridinedione.

WR 243251 is a dihydroacridinedione that was evaluated for antimalarial blood schizonticidal activity in vitro and in vivo. The in vitro doses calculated to kill 50% of organisms were 11 nM for a chloroquine-susceptible, mefloquine-resistant standard strain and 25 nM for a chloroquine- and pyrimethamine-resistant standard strain. The total dose needed to cure 100% of mice infected with a drug-susceptible strain of Plasmodium berghei was 12 to 20 mg/kg of body weight for both oral and subcutaneous administration. The regimen needed to cure 100% of Aotus monkeys infected with Plasmodium falciparum was 8 mg/kg/day for 3 days (chloroquine-susceptible strain) and 16 mg/kg/day for 3 days (chloroquine-resistant strain). The 100% curative doses for Aotus monkeys did not increase for parasites previously exposed to subcurative doses. The absolute value of the curative doses of WR 243251 was comparable to or lower than the values for clinical antimalarial agents. The high absolute activity, comparability of activities against susceptible and resistant parasites, and inability to induce resistance by exposure to subcurative doses suggest that WR 243251 has strong potential as a blood schizonticidal agent.

Acridines↗
PubMed1994

Efficacy of azithromycin as a causal prophylactic agent against murine malaria.

The efficacy of the newly marketed azalide azithromycin was compared with that of the clinical agent doxycycline in a murine model of sporozoite-induced malaria. Drug was administered once; Plasmodium yoelii sporozoites were administered 2 h later; survival at day 60 was determined. For parenterally administered drug, 160 mg of azithromycin or doxycycline per kg of body weight was 100% effective; 40 mg of azithromycin per kg was 80% effective, but 40 mg of doxycycline per kg was 40% effective. Orally administered azithromycin was somewhat less effective than parenterally administered drug, consistent with the 37% clinical oral bioavailability of this agent. For orally administered azithromycin, 160 mg/kg was 100% effective and 40 mg/kg was 40% effective. The efficacy of azithromycin in comparison with that of doxycycline and the known prolonged levels of azithromycin in the livers of humans suggest that azithromycin has potential as a clinical causal prophylactic agent for malaria.

Animals↗
PubMed1993

Perineuronal satellitosis in the human hippocampal formation.

A previously unreported example of perineuronal satellitosis in the medial CA1 and adjacent subiculum in the human hippocampal formation is described. This phenomenon is characterized by a clustering of glial cells in relation to the perikarya of a subpopulation of neurons in the deep pyramidal layer and around most neurons scattered in the stratum oriens and subcortical white matter. Most of the perineuronal satellite glia were identified as oligodendrocytes based on their nuclear chromatin patterns and antigenic properties. Satellite oligodendrocytes were mostly of the medium dense variety. A type of satellite glia with nuclear features of the dark oligodendrocyte could not be identified unequivocally using the antigenic criteria employed in this study.

Adult↗
PubMed1993

Glycoside antibiotics alone and combined with tetracyclines for prophylaxis of experimental cryptosporidiosis in neonatal BALB/c mice.

Glycoside antibiotics including the macrolide antibiotics azithromycin, clarithromycin, and erythromycin and the aminoglycoside paromomycin were administered alone or combined with doxycycline, minocycline, or tetracycline to neonatal BALB/c mice experimentally infected with Cryptosporidium parvum. Glycosides at 100 or 200 mg/kg of body weight and tetracyclines at 50 mg/kg of body weight were dissolved in dimethylsulfoxide (DMSO), which was then diluted with phosphate-buffered saline (PBS) and given orally by gavage. Drugs were administered at 0, 24, 48, and 72 hr postinfection (PI) for prophylaxis. Histologic sections of ileum, cecum, and colon from tissues fixed at 96 hr PI were examined microscopically to determine the number of developing parasites and assign a quantitative score based on infectivity. All groups that received glycosides had significantly (P < 0.01) lower scores than controls that received only DMSO/PBS. A range in efficacy was apparent. None or extremely few parasites were found in paromomycin- and azithromycin-treated groups, whereas few to moderate numbers of parasites were found in erythromycin- and clarithromycin-treated groups. The addition of tetracyclines did not consistently result in significantly lower scores.

Animals↗
PubMed1993

Paromomycin is effective as prophylaxis for cryptosporidiosis in dairy calves.

Of 16 experimentally infected neonatal dairy calves, 12 were fed paromomycin twice daily in their milk for 11 consecutive days beginning 1 day before oral inoculation with 1.5-2.0 x 10(6) oocysts of Cryptosporidium parvum. Four calves each in groups A, B, C, and D received total daily doses of 100, 50, 25, and 0 mg of paromomycin per kilogram of body weight, respectively. From birth until 28 days of age feces from each calf were examined for diarrhea, and oocysts were enumerated, rectal temperature was recorded, and weight gain was determined. Total days of diarrhea, severity of diarrhea, the total number of days oocysts were shed, and the number of oocysts shed were significantly less in group A than in the unmedicated group D. The severity of diarrhea was also significantly less in groups B and C than in group D. Oocysts were not detected in feces from calves in group A. Except for 1 calf, oocysts were not detected from calves in groups B and C during the first week the drug was administered and those calves that shed oocysts began shedding at or near the end of paromomycin administration or more than 1 wk after treatment ended. Frequency of fever and weight gains did not vary significantly between the unmedicated and medicated groups except for group C, calves of which gained significantly less weight than those in all other groups.

Animals↗
PubMed1992

Radial keratotomy in a patient with keratoconus.

A 30-year-old white male with keratoconus had uneventful radial keratotomy in his right eye. Although a good initial response was obtained with total correction of myopia and astigmatism, by 18 months postoperatively the entire result had regressed and the patient demonstrated reformation of the cone and regression to high myopia. Scarring occurred in the three inferior cuts overlying the cone. Cuts on the horizontal axis, and superiorly (above the cone), had a normal appearance with normal wound healing. Because of the nature of the wound healing overlying the portion of the cornea affected by the keratoconus and because of the total regression of effect, radial keratotomy in patients with keratoconus does not appear to be an effective modality.

Adult↗
PubMed1992

Effects of in utero phrenic nerve section on the development of collagen and elastin in lamb lungs.

Interference with fetal breathing movements is known to retard morphologic development of the lung and to reduce compliance. We hypothesized that the lower compliance might be in part due to effects on lung structural proteins. We studied the effects of phrenic nerve section in utero on lung compliance and on the lung contents of collagen, elastin, and DNA. At 110 to 112 days of gestation, one fetal lamb in each of 12 twin pregnancies had either both phrenic nerves cut (PX) or a sham operation (S). The other twin was left unoperated (Upx, Us) as a control. They were killed 14 to 22 days later, and the concentrations in lung parenchyma of collagen (as hydroxyproline HPro), elastin, and DNA were measured, together with lung compliance and dry and wet weight. Paired comparisons were made (PX versus Upx and S versus Us). Both operated groups (PX, S) had smaller lungs with lower water content than did their unoperated twins. Absolute static compliance in PX was reduced, but compliance relative to lung weight was unchanged, and there was no significant difference between S and Us. There were no significant effects of PX on the concentrations of HPro, elastin, and DNA, or on the elastin/collagen ratio. Compliance was not correlated with either HPro or elastin content. HPro content increased significantly with gestational age in all groups. It is concluded that phrenic nerve section retards the increase of lung compliance and possibly air space, but it does not affect the overall rate of lung cell proliferation or of deposition of elastin or collagen.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Experimental radial thermokeratoplasty in rabbits.

Radial thermokeratoplasty is a new technique designed to reduce hyperopia. We evaluated the histopathological effect at 2, 4, and 30 days following radial thermokeratoplasty in rabbit corneas. Surgical complications included variable-sized coagulations and microperforations in two eyes. Light microscopy disclosed that the burns were 90% in depth and healing occurred by epithelial ingrowth. The stroma surrounding the coagulation was acellular early but keratocyte repopulation was apparent by 30 days. A retrocorneal membrane four to five cells thick was noted at the early time points; however, by 30 days only a double layer of spindle-shaped cells remained. By electron microscopy, damage to surrounding endothelial cells was estimated to be 300 microns (from the center of the coagulation). Our results suggest that radial thermokeratoplasty, which utilizes a temperature of 600 degrees C placed within the cornea to a depth of 90%, will cause significant damage to the corneal endothelium beneath and surrounding the coagulation site.

Animals↗
PubMed1988

Congenital cerebrospinal fluid-containing intracranial abnormalities: a sonographic classification.

Ultrasound is useful as a primary modality for diagnosis of complex nonhydrocephalic intracranial malformations. We present 10 cases of intracranial cerebrospinal fluid containing abnormalities that may be diagnosed by ultrasound. Congenital abnormalities presented include holoprosencephaly, hydranencephaly, agenesis of the corpus callosum with interhemispheric cyst, porencephaly, schizencephaly, and arachnoid cyst. Ultrasound may be used in the fetus or neonate in detecting and separating these abnormalities from hydrocephalus.

Abnormalities, Multiple↗