Biomedical subjects
B Katz
Publications and source records attributed to B Katz.
Lessons on dermoscopy: case #9. Congenital melanocytic nevus.
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Lessons on dermoscopy: case #10. Diagnosis: the differential clinical diagnoses were dysplastic nevus, malignant melanoma, and lichen planus-like keratosis.
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Lessons on dermoscopy. Diagnosis: seborrheic keratosis.
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Electrodiagnostic reference values for the lateral antebrachial cutaneous nerve: standardization of a 10-cm distance.
OBJECTIVE: To derive a normative database for nerve conduction values of the lateral antebrachial cutaneous nerve (LACN) using a large and varied subject population. DESIGN: Descriptive study. SETTING: Private office or university-based clinic. PARTICIPANTS: Volunteers (n = 213), recruited through advertisements, who met inclusion criteria. MAIN OUTCOME MEASURES: Onset latency, peak latency, baseline-to-peak amplitude, peak-to-peak amplitude, area, rise time, duration, side-to-side differences, and the effects of age, race, sex, height, and body mass index (BMI) were investigated on 213 healthy volunteers between the ages of 19 and 79 years. RESULTS: The mean +/- SD onset latency was 1.7+/-0.2 ms. The 95th and 97th percentile values for onset latency were 2 and 2.1 ms, respectively. Mean peak latency was 2.2+/-0.2 ms. Both the 95th and 97th percentile values for peak latency were 2.5 ms. Mean onset to peak amplitude was 18+/-10 microV. The 5th and 3rd percentile values for onset to peak amplitude were 6 and 5 microV, respectively. Mean peak-to-peak amplitude was 22+/-15 microV. The 5th and 3rd percentile values for peak-to-peak amplitude were 7 and 6 microV, respectively. Mean area was 11+/-7nV-s, mean rise time was 0.5+/-0.1 ms, and mean duration was 1.1+/-0.2 ms. Mean side-to-side difference was 0.1+/-0.2 ms for onset latency, 0.1+/-0.2 ms for peak latency, 1+/-12 microV for onset to peak amplitude, and 0+/-17 microV for peak-to-peak amplitude. Increasing age and BMI were associated with lower mean amplitudes, but did not affect the lower limits of normal. CONCLUSION: These normative values will be useful in electrodiagnostic study of the LACN.
A bioassay evaluation of the urinary antibacterial efficacy of low dose prophylactic antibiotics in children with vesicoureteral reflux.
PURPOSE: We evaluated by means of a bioassay the efficacy of 4 different antibiotics administered in a prophylactic dose to children with vesicoureteral reflux. MATERIALS AND METHODS: A total of 159 urine samples from 53 children taking prophylactic antibiotics with proved vesicoureteral reflux were tested. The children were divided into 4 groups according to the antibiotic given, which included nalidixic acid, cephalexin, cotrimoxazole and cefixime. Urine samples were collected in the morning, at noon and in the evening, and each sample was bioassayed for growth inhibition of a standard Escherichia coli. The urine volume used was specifically determined for each antibiotic, and growth inhibition by this specific volume was equivalent to that produced by standard diffusion disks. In addition, the specific gravity, which reflected urinary concentration of each sample, was measured. RESULTS: Mean patient age plus or minus standard deviation of the 4 groups was 53 +/- 41 for nalidixic acid, 23 +/- 34 for cephalexin, 55 +/- 35 for cotrimoxazole and 47 +/- 35 months for cefixime, respectively. In children less than 2 years old specific gravity was higher in the morning (1.021 +/- 0.0006 versus 1.0008 +/- 0.0004 at 8 a.m. and 2 p. m., respectively, p <0.05). In contrast, in children older than 4 years the specific gravity was higher in the afternoon and evening hours (1.019 +/- 0.003 versus 1.007 +/- 0.003 at 2 p.m. and 8 a.m., respectively, p <0.05). The percentage of patients who demonstrated growth inhibition in all 3 samples of the test day was 7%, 6%, 69% and 44% for nalidixic acid, cephalexin, cotrimoxazole and cefixime, respectively (p <0.001 for cotrimoxazole and cefixime versus nalidixic acid and cephalexin. Divided into morning, noon and evening, the percentage of samples that demonstrated growth inhibition was 85.7%, 21.4% and 7.1% for nalidixic acid, 37.5%, 12. 5% and 6.3% for cephalexin, 100%, 92.3% and 76.9% for cotrimoxazole and 100%, 77.7% and 55.5% for cefixime, respectively. A direct correlation was found between specific gravity and growth inhibition (r = 0.55, p <0.001). CONCLUSIONS: Urine concentration during the day is dependent on age with older children having more concentrated urine in the latter part of the day. Growth inhibition is enhanced by concentrated urine. Compared to nalidixic acid and cephalexin, cotrimoxazole and cefixime produce a sustained bactericidal effect for about 60% of a 24-hour day due to the longer half-life.
Lessons on dermoscopy #11. Solar lentigo.
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Regional distribution of optic nerve head blood flow.
BACKGROUND: Advanced glaucoma typically results in damage of the temporal neuroretinal rim. As vascular factors are of pathogenic importance in the development of glaucomatous damage, the present study investigated whether regional differences in perfusion might be the reason for the preferential damage of the temporal neuroretinal rim. MATERIAL AND METHODS: Blood flow of the neuroretinal rim was measured with the laser Doppler flowmeter (LDF) Oculix 4000 (continuous measurement of an area of 160 microm diameter) and the Heidelberg retina flowmeter (HRF). Both instruments measure the capillary blood flow (flow), the relative velocity of erythrocytes (velocity) and the relative volume of moving erythrocytes (volume). We examined one randomly chosen eye of 55 healthy subjects without history of glaucoma aged 22-57 years (mean 30 years). Each subject was measured with the LDF and HRF, each time nasally and temporally, away from visible vessels. The intraocular pressure (IOP) was measured with the Goldmann tonometer. Heart rate and systolic and diastolic blood pressure were measured. RESULTS: The LDF measurements of the optic nerve head showed nasal flow of 12.4+/-5.6 AU and temporal flow of 9.8+/-3.6 AU. The HRF showed a nasal flow of 477+/-161 AU and a temporal flow of 368+/-166 AU. The volume measurements done by LDF showed nasally a value of 0.68+/-0.40 AU and temporally a value of 0.46+/-0.21 AU. The HRF volume measurements showed nasal values of 16.1+/-4.3 AU and temporal values of 13.0+/-4.0 AU. The LDF velocity values were nasally 0.22+/-0.05 kHz and temporally 0.26+/-0.05 kHz. HRF measurements showed velocity values of 1.7+/-0.5 kHz nasally and 1.3+/-0.6 kHz temporally. The differences were highly statistically significant for flow (LDF P=0.00007, HRF P=0.0005), volume (LDF P=0.00002, HRF P=0.00004) and velocity (LDF P=0.0002, HRF P=0.00004). The IOP was 12.6 mmHg. Blood pressure was 118/75 mmHg and the heart rate was 73 beats per minute. There was no correlation between age, IOP, BP and HR and the HRF/LDF measurements. CONCLUSION: The measurements with two different methodologies showed a decreased blood flow of the temporal neuroretinal rim compared to the nasal side. These local differences might be one reason for the preferential damage of the temporal neuroretinal rim in advanced glaucoma.
The fate of the dropped gallstones during laparoscopic cholecystectomy.
Stones can be spilled from the gallbladder during laparoscopic cholecystectomy. These stones can be left in the peritoneal cavity or trapped at the trocar site. The potential late sequel and associated morbidity are not well documented. We reviewed the records of four patients who underwent laparoscopic cholecystectomy at Mount Sinai Medical Center in New York City who suffered from late complications attributed to gallstones left in the peritoneal cavity or abdominal wall. Four patients presented 1-14 months after laparoscopic cholecystectomy with intraabdominal and abdominal wall abscesses. The spillage of gallstones was noticed during the initial operation only in one of the patients. Three patients required laparotomy and open drainage of intraabdominal abscesses with drainage of pus and gallstones after failed attempts at percutaneous drainage. Two patients underwent local exploration of an abdominal wall abscess containing stones. Stones left in the abdominal cavity or trapped in trocar sites after laparoscopic cholecystectomy can cause serious late complications requiring repeated surgical interventions. Every effort should be made in order to avoid spillage of stones during dissection of the gallbladder and cystic duct and during retrieval of the gallbladder through the abdominal wall.
8-methyl-pyridoxatin: A novel N-hydroxy pyridone from fungus OS-F61800 that induces erythropoietin in human cells.
In the course of screening for small-molecule modulators of erythropoietin gene expression, a novel N-hydroxy pyridone was isolated from a culture of OS-F61800. Its structure was elucidated by extensive 1H and 13C NMR spectroscopic and chemical studies. This compound induced erythropoietin gene expression fivefold at a concentration of 0.3 microM, which is about threefold greater potency than our previously identified erythropoietin inducers.
Altered vascular reactivity following partial nephrectomy in the rat: a possible mechanism of the blood-pressure-lowering effect of heparin.
BACKGROUND: This study was designed to assess whether the antihypertensive effect of heparin in rats after renal mass reduction (RMR) is related to changes in nitric oxide activity, and to study in vitro the altered behaviour of resistance-sized arteries induced by chronic administration of heparin. METHODS: Male Wistar rats were assigned to one of two experimental protocols. In the first protocol, RMR rats received heparin (250 units/day s.c.) and tail systolic blood pressure (SBP) was measured weekly for 4 weeks. In a subgroup, urinary nitrate excretion (UNO3) and in vitro vascular reactivity of isolated perfused mesenteric arterial beds were measured 2 weeks after RMR. The second protocol assessed whether inhibition of NO synthesis with L-NAME (70 mg/l added to the drinking water) prevents the blood-pressure-lowering effect of heparin. RESULTS: In untreated RMR rats SBP increased from 111+/-3 mmHg to 127+/-5 mmHg at 2 weeks and 139+/-5 mmHg at 4 weeks. In contrast, in RMR rats treated with heparin, SBP was 114 +/-3 mmHg at 2 weeks and 115+/-4 mmHg at 4 weeks (P<0.05 for both). Treatment with L-NAME increased SBP both in untreated and heparin-treated RMR groups. Two weeks after nephrectomy daily urinary nitrate increased significantly more in RMR rats treated with heparin than in untreated RMR rats (22+/-2 vs 14.2+/-2.3 micromol/day, P<0.05). In vitro studies performed at 2 weeks showed that vessels of untreated RMR rats had a blunted vasodilator response to acetylcholine that was restored to levels similar to that of controls in the heparin-treated group. CONCLUSIONS: These results suggest that, in rats after renal ablation, heparin may exert its antihypertensive effect, at least in part, by affecting the altered behaviour of resistance vessels during the development phase of hypertension. Increased NO production may contribute to this effect.
Anorexic eating attitudes and behaviors of male and female college students.
This study examined gender differences in eating attitudes and behaviors in a sample of 471 undergraduate college students. The prevalence of symptomatology indicative of anorexia was determined using the Eating Attitudes Test (EAT-26). In addition, the family climate, parent-child dynamics, and self-concept of students with and without maladaptive eating attitudes and behaviors were compared, and the relationship between eating attitudes/behaviors and current psychological distress was examined. Anorexic symptomatology was found for 20% of the females and 10% of the males. In general, students without symptomatic attitudes and behaviors had a more positive self-concept and reported less psychological distress than did those with eating disturbances. The findings suggest that eating problems may be more prevalent among males than previously estimated.
Epolones: novel sesquiterpene-tropolones from fungus OS-F69284 that induce erythropoietin in human cells.
In the course of our screening for small molecule modulators of erythropoietin gene expression, two novel sesquiterpene tropolones and pycnidone were isolated from a culture of OS-F69284 (ATCC 74390). Their structures were elucidated by extensive 1H and 13C NMR spectroscopic studies and chemical reactions. These compounds induced erythropoietin gene expression 5-fold at a concentration of 1-1.6 microM.
Nurse perceptions of ostomy patients & their ostomy care competence.
The nursing role of caring for ostomy patients has evolved from the bedside nurse to an enterstomal therapist (ET) or a nurse clinical specialist with ostomy care experience. Routine practice calls for staff nurses and physicians to refer patients with a new ostomy or patients with stoma problems to these specialists. The responsibility for successful outcomes typically falls on these specialized nurses.
Destruxin-A4 chlorohydrin, a novel destruxin from fungus OS-F68576: isolation, structure determination, and biological activity as an inducer of erythropoietin.
In the course of screening for small-molecule modulators of erythropoietin gene expression, five destruxins were isolated from the fungal culture of OS-F68576. The structures were elucidated by extensive 1H and 13C NMR spectroscopy and by hydrolytic modification. One compound (destruxin-A4 chlorohydrin, 1) is a novel destruxin. All these compounds induced erythropoietin gene expression 5-fold at concentration of 0.2-2 microM.
Prevention of experimental Haemophilus ducreyi infection: a randomized, controlled clinical trial.
Human subjects were infected with Haemophilus ducreyi. All subjects developed papules and were randomized to treatment with a single dose of azithromycin (1 g) or ciprofloxacin (500 mg). At weekly intervals, volunteers were reinoculated with H. ducreyi, and drug concentrations were measured in peripheral blood mononuclear cells (PBMC). When papules developed, the subjects were treated with antibiotics and dismissed from the study. Eight of the ciprofloxacin-treated subjects developed papules 1 week after the initial treatment, and the ninth subject developed disease 2 weeks after treatment. The 9 azithromycin-treated subjects developed papules 4-10 weeks (mean, 6.8) after the initial treatment (P < .001). Azithromycin was detected in PBMC for 3-6 weeks (mean, 4). Pre- and posttreatment lesions had histology typical of experimental chancroid or were culture positive. Azithromycin prevents experimental chancroid for nearly 2 months. These findings have implications for strategies to prevent chancroid.
Effect of chronic fluoride exposure in uremic rats.
This study was conducted to test the hypothesis that the margin of safe fluoride exposure is narrowed in rats that are physiologically compromised by renal dysfunction. The study objective was to determine whether increases in fluoride retention and tissue fluoride levels in rats with surgically induced renal insufficiency result in toxic fluoride effects not ordinarily observed in healthy animals. Uremic and sham-operated control rats received 0 microg/ml, 5 (0.26 mmol/l), 15 (0.79), or 50 microg/ml (2.63 mmol/l) of fluoride in their drinking water for 3 or 6 months. Fluoride retention was monitored, and, following euthanasia, tissue fluoride and biochemical markers of tissue function were analyzed. Selected tissues were saved for histology, and bone marrow cells were harvested for determining the frequency of sister chromatid exchange, a marker of genetic damage. In spite of significantly higher levels of fluoride in the tissues of the animals with renal insufficiency, there were no clinically adverse, fluoride-induced, extraskeletal physiological, biochemical, or genetic effects of chronic exposure to common levels of fluoride in these rats.
Isolation and characterization of the fungal metabolite 3-O-methylviridicatin as an inhibitor of tumour necrosis factor alpha-induced human immunodeficiency virus replication.
The cytokine tumour necrosis factor alpha (TNF-alpha) has been shown to play a role in human immunodeficiency virus (HIV) replication by activating transcription of the provirus in both T cells and macrophages. Therefore, agents that block TNF-alpha-induced HIV expression could have therapeutic value in the treatment of AIDS. We have sought to identify antiviral agents that block TNF-alpha induction of HIV LTR-directed transcription, using a cell-based, virus-free assay system in automated high-throughput screening. HeLa cells were transfected with an HIV LTR-luciferase reporter plasmid and a stable line was isolated in which TNF-alpha increased luciferase production by two- to threefold. This cell line was used to screen approximately 15,000 fungal extracts. An inhibitory activity specific for TNF-alpha-induced HIV LTR transcription was observed in culture OS-F67406. The active component was isolated and identified as a known metabolite, 3-O-methylviridicatin, by NMR and mass spectrometry. No biological activity has been associated with this compound previously. This compound blocks TNF-alpha activation of the HIV LTR in the HeLa-based system, with an IC50 of 5 microM, and inhibited virus production in the OM-10.1 cell line, a model of chronic infection responsive to induction by TNF-alpha, with an IC50 of 2.5 microM.