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Biomedical subjects

L R Watson

Publications and source records attributed to L R Watson.

At least 19 recordsLinked to original sources
PubMed1998

Replication and pathogenesis of white sturgeon iridovirus (WSIV) in experimentally infected white sturgeon Acipenser transmontanus juveniles and sturgeon cell lines.

Characteristics of the in vitro propagation of the white sturgeon iridovirus (WSIV) were examined in 6 sturgeon cell lines. One new cell line originating from gonadal tissues (WSGO) produced up to 12-fold more WSIV [approximately 22 TCID50 (50% tissue culture infective dose) cell-1], than that of a previously established reference spleen cell line (WSS-2). Infected WSGO cell cultures were examined using phase microscopy, viral infectivity assay and transmission electron microscopy (TEM). At 15 degrees C, both mature virions and infectious virus were first detected after 7 d post-infection. Capsids acquired envelopes in the cytoplasm and virions remained primarily cell-associated during the 35 d replication cycle. Cellular changes including hyper-refractility and cytoplasmic swelling with dense cytoplasmic inclusions correlated to extensive proliferation of cytoplasmic vesicles and viral assembly sites. These cytological characteristics corresponded to changes in target cells of WSIV-infected juvenile white sturgeon following bath challenge. Microscopic changes in stained tissue sections of the host epithelium were detected 4 d post-challenge, approximately 8 d prior to the onset of clinical signs. Hypertrophied Malpighian cells surrounded by a prominent pericellular cisternum characterized epithelial lesions in the skin. Similar changes to epithelial cells of the barbels, olfactory organs and esophagus were also observed. Destruction of the sensory epithelium is suggested as a cause for cessation of feeding which occurs early in the infection of white sturgeon juveniles with WSIV.

Animals↗
PubMed1998

Following the child's lead: mothers' interactions with children with autism.

This study examined the extent to which mothers of preschool children with autism use language that is related to the child's focus of attention. Fourteen mother-child dyads involving preschool children with autism participated in this study, along with 14 matched dyads involving typically developing preschool children. Both groups were observed during 15 minutes of free play. Results revealed that the mothers of children with autism directed verbalizations to something within the child's focus of attention as frequently as the mothers of typically developing children. Thus, children with autism had as many opportunities to benefit from verbal input related to their focus of attention as did typically developing children. However, mothers of children with autism directed verbalizations to something not within the child's focus of attention more frequently than mothers of typically developing children. This nonrelated input may have reflected the mothers' attempts to adapt to their children's difficulties in attention and interaction.

Attention↗
PubMed1997

Clinical value of renovascular resistive index measurement in the diagnosis of acute obstructive uropathy.

PURPOSE: We evaluated the clinical use of the renal resistive index in identifying patients with acute urinary tract obstruction. MATERIALS AND METHODS: Of 54 patients with suspected acute urinary tract obstruction who underwent measurements of renal resistive index 19 had unilateral obstruction documented with excretory urography and comprise our study sample. The contralateral nonobstructed kidneys served as controls. Criteria for obstruction were a resistive index of 0.70 or greater or a side to side difference of 0.10 or greater. We calculated sensitivity, specificity, and positive and negative predictive values. RESULTS: Sensitivity for obstruction was 42% with 11 false-positive cases, specificity was 79%, and positive and negative predictive values were 67 and 57%, respectively. CONCLUSIONS: Renal resistive index measurements are not valuable in detecting acute urinary tract obstruction.

Acute Disease↗
PubMed1997

The impact of sonography on the diagnosis of scrotal disorders.

PURPOSE: We assessed the impact of ultrasound on the referring urologist diagnosis of scrotal disorders. MATERIALS AND METHODS: University urologists (6 attending and 3 resident physicians) in a clinic setting completed questionnaires before and after on 35 patients with scrotal symptoms. The physicians were requested to estimate the probability (0 to 100%) of their most likely diagnosis before and after receiving the sonographic information. We calculated the mean change in diagnostic percentage confidence and also the proportion of patients whose pre-sonographic diagnosis was changed. RESULTS: Scrotal ultrasound changed the initial diagnosis in 11 of 35 patients (32%, 95% confidence interval 19 to 49). The mean percentage gain in diagnostic certainty from ultrasound was 29% (95% confidence interval 20 to 39, p < 0.001). CONCLUSIONS: Scrotal ultrasound has considerable impact on referring urologist diagnosis of scrotal abnormalities.

Diagnosis, Differential↗
PubMed1996

Ultrasound anatomy of the normal male reproductive tract.

Ultrasound is being used with increasing frequency in the evaluation of the male reproductive tract. To detect abnormalities, it is important to have a comprehensive understanding of the normal anatomy and normal variations. In this article, the ultrasound anatomy of the scrotum, penis, prostate, and seminal vesicles is presented. Because ultrasound is a very visual process, the anatomy is presented not only with text, but also through the liberal use of ultrasound images and associated diagrams. Ultrasound is both an operator- and equipment-dependent procedure and, where appropriate, we have included technical discussions regarding ultrasound equipment and settings.

Genitalia, Male↗
PubMed1994

Tubular ectasia of the rete testis: a benign condition with a sonographic appearance that may be misinterpreted as malignant.

Tubular ectasia of the rete testis is a recently recognized entity whose sonographic appearance has been described principally in the radiological literature. The sonographic features of this benign process must be appreciated by urologists as well so that is not mistaken for malignancy. We report 3 cases showing the spectrum of this process and review the literature.

Adult↗
PubMed1994

Scrotal ultrasound for evaluation of subacute testicular torsion: sonographic findings and adverse clinical implications.

There is an increased use of scrotal ultrasound in the clinician's office and emergency room for the investigation of scrotal pain. The use of real-time scrotal ultrasound for the diagnosis of testicular torsion has been described in the literature. A false-negative ultrasound examination can postpone the diagnosis of torsion and result in testicular loss. We examined 6 patients 1 day to 18 years old who had subacute testicular torsion with scrotal symptomatology (pain and/or swelling) for longer than 8 hours (range 12 hours to 6 days). Scrotal ultrasound was performed as 1 of the initial tests. A common sonographic pattern was an inhomogeneous testicle with hypoechoic areas alternating with hyperechoic areas and thickening of adjacent scrotal tissue. Another common finding was an edematous hyperechoic epididymis and a small hydrocele. In 4 of the 6 cases these nonspecific findings suggested a misleading diagnosis of tumor or epididymitis and resulted in delay of surgery and testicular loss. Treatment was not delayed in only 2 patients in whom the diagnosis of torsion was made initially by history and physical examination, and ultrasound was done for interest only. Misdiagnosis of intratesticular blood flow and some potential pitfalls of scrotal imaging by color Doppler ultrasound are discussed. We conclude that real-time scrotal sonography can be misleading in cases of subacute testicular torsion and, therefore, it should not be used in this clinical setting.

Acute Disease↗
PubMed1992

Laparoscopic surgery in urology.

In recent months, laparoscopy has been used for such urological procedures as varicocelectomy, pelvic lymph node dissection and even nephrectomy. It would appear that laparoscopic surgery is going to make an important contribution to the field of endourology. In order to assess the current status and value of laparoscopic techniques to urologists, we have reviewed the history of laparoscopy in general and urologic laparoscopy in particular.

England↗
PubMed1992

Sonographic detection of ureteral calculi in patients with normal excretory urography.

We report 3 cases of nonobstructing distal ureteral calculi diagnosed by sonography in which excretory urography was normal. In each case sonography was performed because of high clinical suspicion for a ureteral stone. In 2 patients a stone was impacted at an edematous ureteral orifice. All 3 patients subsequently passed the stone spontaneously. A high resolution ultrasound examination should be performed on patients with a history suggestive of ureteral calculus despite a normal excretory urogram.

Adult↗
PubMed1991

Cosmetic treatment of shagreen patches in selected patients with tuberous sclerosis.

Patients with mild forms of tuberous sclerosis may request cosmetic treatment of skin hamartomas. Treatment may consist of planning of an elevated shagreen patch with a Reese dermatome and/or laser treatment of facial angiofibromas. These precise patients, i.e., patients with a forme fruste of tuberous sclerosis, are more likely to have pulmonary involvement than patients with the usual complete disease form. A chest x-ray should be obtained in these patients to rule out pulmonary involvement. Half the patients with pulmonary involvement of tuberous sclerosis die an avoidable death from spontaneous pneumothoraces. Positive-pressure ventilation during anesthesia in these patients should be avoided or monitored closely.

Adult↗
PubMed1991

The intratracheal administration of endotoxin and cytokines. I. Characterization of LPS-induced IL-1 and TNF mRNA expression and the LPS-, IL-1-, and TNF-induced inflammatory infiltrate.

Endotoxin (LPS), one of the major proinflammatory constituents of the cell walls of gram-negative bacteria, induces alveolar macrophages to express interleukin-1 (IL-1) and tumor necrosis factor (TNF) messenger RNA (mRNA), peaking at 1 hour in vitro. Intratracheal injection of LPS induces IL-1 and TNF mRNA expression in vivo in whole-lung RNA preparations. Interleukin-1 mRNA is not constitutively detected. In the case of TNF, however, a constitutively-expressed hybridization band is noted at 1.6 kb, whereas the LPS-induced hybridization band is noted at approximately 1.95 kb. Intratracheal injection of LPS induces an intra-alveolar inflammatory reaction composed of a neutrophilic exudate, peaking at 6 to 12 hours, a monocytic exudate peaking at 24 hours, and a lymphocytic exudate peaking at 48 hours, as quantitated by bronchoalveolar lavage. Intratracheal injection of IL-1 recapitulates the kinetics and relative magnitudes of the acute neutrophilic and chronic monocytic and lymphocytic inflammatory sequence. Intratracheal injection of TNF also induces an acute intraalveolar neutrophilic exudate, but TNF is much less potent of an inflammatory stimulus than IL-1. The effects of recombinant IL-1 and TNF are not due to LPS contamination, as shown by abrogation of the cytokines' inflammatory activity by boiling. In conclusion, LPS induces IL-1 and TNF mRNA expression in vitro in alveolar macrophages and in vivo in pulmonary tissue, and intratracheal injection of IL-1 and TNF recapitulates the LPS-induced pulmonary inflammatory sequence, strongly supporting the hypothesis that these cytokines play an important in vivo role in the pathogenesis of gram-negative bacterial pneumonia.

Animals↗
PubMed1990

In vivo hematologic effects of recombinant human macrophage colony-stimulating factor.

Macrophage colony-stimulating factor (recombinant human M-CSF) given as a single intravenous injection to Lewis rats induces a dose-dependent peripheral monocytosis, neutrophilia, and lymphopenia. The monocytosis peaks at 28 to 32 hours with a seven- to eightfold increase in the number of circulating monocytes and promonocytes. The peripheral monocytosis is accompanied by a slight increase in marrow blasts, promonocytes, and monocytes. A monocytopenia reaching a nadir at 15 minutes precedes the monocytosis, suggesting that M-CSF activates circulating monocytes and causes intravascular margination. The M-CSF-induced neutrophilia and lymphopenia are relatively mild in magnitude, are observed between 2 and 16 hours after injection, and are no longer evident at later time-points. The monocytosis was at least partially inhibited by dexamethasone. M-CSF-induced monocytosis most likely reflects a direct effect of M-CSF on marrow monocyte precursor proliferation, maturation, and release, whereas the neutrophilia and lymphopenia may reflect indirect effects mediated by the known ability of M-CSF to cause the release of other cytokines.

Animals↗
PubMed1989

Colonic mucosectomy using laser photodynamic therapy.

Photodynamic therapy (PDT) involves photosensitizing tissue and then activating it with monochromatic light, causing necrosis. Precise control of the extent of injury should be possible by varying the energy density of the light applied to the target tissue. We tested the sensitivity of colonic tissue to PDT by injecting 10 mg/kg Photofrin II intraperitoneally in 10 rats. After 24 hr the left colon was opened and cleansed. A 1.0-cm2 area of mucosa was exposed to 630 nm (red) light produced by an argon-pumped dye laser. Pairs of rats were treated with energy densities of either 10, 20, 40, 60, or 80 J/cm2, controlled by varying exposure times. After 48 hr, we sacrificed the rats and fixed, sectioned, and stained the left colons. The depth of injury was measured with an ocular micrometer and expressed as a percentage of normal bowel wall thickness. A curve was fit to the data points by computerized nonlinear regression. The relationship between depth of injury (Y) and energy density (X) was found to fit the equation Y = 1 - aebx, where constants a = 1.15 and b = -0.0353, (R2 = 0.93, P less than 0.001). The relationship between injury and energy density is biphasic, rising rapidly from 0 to 40 J/cm2 and more slowly after this point, suggesting that colonic mucosa is more sensitive to PDT than muscularis, providing a margin of safety against perforation. Bowel perforation did not occur in this study but is predicted by extrapolation for energy densities of 100 J/cm2 or greater. These data indicate that photodynamic colonic mucosectomy is possible.

Animals↗