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Biomedical subjects

C Rubin

Publications and source records attributed to C Rubin.

At least 55 records · Page 3Linked to original sources
PubMed1998

[Withdrawal syndrome caused by selective serotonin reuptake inhibitors: apropos of a case].

During the past 4 years, several case reports have been published on the withdrawal syndrome which may be observed after acute interruption of a treatment with selective serotonin reuptake inhibiting antidepressants (SSRI). Paroxetine is the most frequently cited antidepressant in the literature, whereas fluoxetine is the less frequently cited of this type of drugs. The withdrawal symptoms appear a few days after stopping treatment or after a decrease of the dose. The typical symptoms are of the gastro-intestinal type, such as loss of appetite, nausea, vomiting, diarrhea and abdominal cramps. Other symptoms are sensation of instability, vertigo, dizziness, headache, malaise, muscular pains, asthenia, as well as a syndrome of pseudo-influenza. Brief electric shocks throughout the body, which last one or two seconds, have also been reported. A case is reported in detail by the authors, who observed some of these symptoms in a patient after stopping his treatment with paroxetine. This withdrawal syndrome may be due to a rebound phenomenon of the serotonergic systems after interruption of the treatment with SSRIs. It is, therefore, recommended that treatment with SSRIs is progressively stopped over a period of several weeks.

Acute Disease↗
PubMed1998

High-energy total body irradiation as preparation for bone marrow transplantation in leukemia patients: treatment technique and related complications.

PURPOSE: Bone marrow transplantation with conditioning regimens that include total-body irradiation (TBI) is widely used in patients with acute lymphoblastic and acute myelocytic leukemias. The major causes of death in this population are relapse of leukemia, infection, and treatment related complications. Our purpose was to achieve a homogenous radiation dose distribution and to minimize the dose to the lungs, liver, and kidneys so that the incidence of organ injury was reduced. METHODS AND MATERIALS: Dose to the bone marrow, midplane, and periphery was quantified by use of thermoluminescent detectors in a bone-equivalent tissue phantom. In an effort to reduce the risk of complications, we treated relapsed or refractory leukemia patients with TBI administered in fractionated, parallel opposed large fields with 24 MV photons, using tissue compensation and partial-transmission lung shielding. Tissue toxicities were then determined. RESULTS: Dose quantitation in bone-equivalent and tissue-equivalent phantoms demonstrated that backscatter and pair production interactions adjacent to bone increased the bone marrow dose by 6 to 11%. At an SSD of 400 cm and at patient diameters of 20 to 40 cm, the percent inhomogeneity across the phantom with 24 MV photons was 0 to 0.3%, compared to 4 to 6% for 6 MV photons. End-organ toxicities consisted of clinical interstitial pneumonitis in six patients, idiopathic interstitial pneumonitis in three patients, renal toxicity in seven patients, and veno-occlusive disease of the liver in one patient. Toxicities did not correlate with fractionation schedule. CONCLUSIONS: Total-body irradiation administered with 24 MV photons increases the dose deposition in bone marrow through pair production and backscatter interactions occurring in bone. Because percent depth dose increases with SSD, the 24 MV beam is more penetrating at a 400 cm distance than at 100 cm and dose homogeneity is improved with higher energies. Thus, the incidence of radiation-mediated injury to lung, liver, and kidney is reduced. This is an effective preparatory regimen for patients with high-risk leukemias requiring bone marrow transplantation.

Adolescent↗
PubMed1998

Transient metabolic changes observed with proton MR spectroscopy in normal human brain after radiation therapy.

PURPOSE: To observe the time course of the proton magnetic resonance spectroscopy (1H-MRS) variations due to radiation therapy on normal human brain. METHODS AND MATERIALS: We followed 11 patients receiving an exclusive external radiation therapy for brain tumor for 8 months. They underwent proton MRS scans before any radiation exposure and 1, 4, and 8 months after they began the radiation therapy. The patients received 60 Gy in tumoral area fractionated over 6 weeks. The contralateral normal brain hemisphere received a radiation dose from 20 to 50 Gy. The main metabolite concentrations (N-acetylaspartate (NAA), choline compounds (Cho), creatine (Cr), and lactate (Lac) were evaluated by the areas of the peaks after peak fitting. Normalized values (NV) were obtained by processing the ratio of the peak area of a given metabolite to the sum of all the spectrum peak areas; ratios (NAA/Cho, NAA/Cr, and Cho/Cr) were processed. One patient, who received panencephalic radiotherapy (30 Gy) after metastasectomy from a primary kidney adenocarcinoma, has been monitored with 1H-MRS eight times for 6 months to observe the onset of the metabolic changes. RESULTS: Changes were observed in irradiated normal brain tissue 4 months after radiation therapy began: the NAA/Cho and NAA/Cr ratios and the NAA (NV) decreased while the Choline (NV) increased. Four months later, normal values were recovered. CONCLUSION: 1H-MRS has the potentiality to detect and to evaluate in vivo early adverse metabolic effects of radiation therapy in the normal human brain. These changes are significant 4 months after the radiation therapy began and appear to resolve over time.

Adult↗
PubMed1998

Suicidal behavior in adolescents: stress and protection in different family contexts.

Recent suicidal behavior was reported on a questionnaire by 14% of 272 high school students. Two-thirds of the suicidal teenagers neither received help nor disclosed their self-harm to anyone. Depression and stress--especially family suicidality, feelings of violation, and sexuality--increased the risk, as did parental separation, divorce, and most dramatically, remarriage. Family cohesiveness helped alleviate the risk in the nonintact families.

Adolescent↗
PubMed1998

Enhancement of fracture healing by low intensity ultrasound.

Fracture healing is a highly complex regenerative process that is essentially a replay of developmental events. These events include the action of many different cell types, a myriad of proteins, and active gene expression that in the majority of cases ultimately will restore the bone's natural integrity. Several biologic and biophysical approaches have been introduced to minimize delayed healing and nonunions, some with promising results. One example of such an approach is low intensity pulsed ultrasound, a noninvasive form of mechanical energy transmitted transcutaneously as high frequency acoustical pressure waves in biologic organisms. Numerous in vivo animal studies and perspective double blind placebo controlled clinical trials have shown that low intensity ultrasound is capable of accelerating and augmenting the healing of fresh fractures. Preliminary evidence suggests efficacy in the treatment of delayed healing and nonunions as well. This article reviews the animal and clinical studies that consider the effects of ultrasound on fracture healing, and the in vivo and in vitro work that strives to identify the biologic mechanism(s) responsible for the ultrasound induced enhancement of osteogenesis and fracture healing.

Animals↗
PubMed1998

[NMR spectroscopy and brain diseases. Clinical applications].

Magnetic resonance spectroscopy (MRS) is a noninvasive means of obtaining metabolic information complementary to magnetic resonance imaging. Its potential is particularly interesting in tissue characterization and follow-up of brain lesions. We present here a review of clinical applications together with a short development of the fundamental principles. From a review of the literature, and our own experience, we discuss the role of MRS in clinical neuroimaging. Despite the small number of clinical applications validated to date, MRS is today a highly useful research tool.

Adult↗
PubMed1997

Pressure regulates osteoclast formation and MCSF expression in marrow culture.

One of the forces generated during skeletal loading is hydrostatic pressure. In the work presented here, the ability of increased pressure to influence recruitment of osteoclasts was evaluated. Murine marrow cultures, with pO2 and pCO2 kept constant, were subjected to either control (1.0 atm) or elevated (1.37 or 2.0 atm) hydrostatic pressure. As compared to control, cultures pressurized for 6 days at 1.37 atm formed less osteoclast-like cells (OCLC) (71 +/- 6% of control, P < 0.0001). A similar degree of inhibition occurred in cultures exposed to pressure during days 2-4 only (62 +/- 6%), while treatment during days 5-7 failed to inhibit the OCLC number relative to control (99 +/- 5%). Delivery of 2.0 atm pressure on days 2-4 generated 52 +/- 4% OCLC compared to control. Since macrophage colony stimulating factor (MCSF)-dependent proliferation of osteoclast precursors occurs during the pressure-sensitive period, semiquantitative RT-PCR for MCSF mRNA was performed after 3 days in 1.37 atm (days 2-4). As compared to controls, pressure caused a decrease in mRNA coding for the membrane bound form of MCSF (71.2 +/- 4% (n = 25, P < or = 0.05), while the MCSF RT-PCR product representing the secreted form showed no consistent change. This lack of response of the soluble MCSF RT-PCR product was expected, as levels of bioassayable MCSF were not altered by pressure. Extrapolating these data to in vivo conditions suggests that load-bearing will inhibit the formation of osteoclasts.

Animals↗
PubMed1997

[Proton magnetic resonance spectroscopy: a metabolic approach of cerebral tumors and their follow-up after external radiation therapy].

The same physical principles are the basis of magnetic resonance spectroscopy (MRS) and magnetic resonance imaging (MRI). Proton MRS is easily performed with clinical magnets (> or = 1.5 T) and may be added to routine MRI studies to provide metabolic information on pathological tissues. It represents an important tool to detect several metabolic compounds. The article will review the current status of proton MRS with a particular emphasis upon its clinical utility for the diagnosis of brain tumors and for the evaluation of the efficacy of radiotherapy.

Brain↗
PubMed1997

Tetracycline prevents cancellous bone loss and maintains near-normal rates of bone formation in streptozotocin diabetic rats.

The skeletal consequences of streptozotocin-induced (STZ) diabetes in the rat are characterized by decreased bone formation and, consequently, reductions in bone mass. Given the ability of tetracyclines to inhibit the breakdown of connective tissue collagen in experimental diabetes (and in other diseases), we examined the potential of this drug to prevent the osteopenia associated with STZ diabetes. To evaluate drug efficacy, the cortical and trabecular bone histomorphometry were analyzed and compared between vehicle-treated control and diabetic rats and control and diabetic rats treated orally with 20 mg/day of minocycline, a semisynthetic tetracycline. In addition, blood and urine glucose, body weight change, tibia lengths, cortical bone densities, and bone ash content were compared. At the end of the 26 day experimental period, diabetic (D) and minocycline-treated diabetic (MTD) rats were polyuric with reduced body weights and significantly elevated blood and urinary glucose levels (p < 0.01). Compared to control (C) and minocycline-treated control (MTC) animals, the periosteal and cancellous bone formation in the D rats had virtually ceased (p < 0.001), and the cancellous bone mass in the tibial metaphysis was reduced 47% (p < 0.01). In contrast, bone formation rates in the MTD animals were increased compared to the D rats (p < 0.001), while cancellous bone areas in the MTD animals were essentially equivalent to those observed in the C and MTC groups. Moreover, growth plate thickness, reduced 43% in the D rats, was preserved in the diabetic animals treated with minocycline. These results demonstrate that minocycline treatment of the streptozotocin diabetic rat maintains normal bone formation, normalizes growth plate thickness, and prevents cancellous bone loss.

Administration, Oral↗
PubMed1996

Comparison of nonrandomized trials with slow-release sodium fluoride with a randomized placebo-controlled trial in postmenopausal osteoporosis.

The results of slow-release sodium fluoride (SR-NaF) treatment in two nonrandomized trials involving 65 patients with postmenopausal osteoporosis from the primary site and 121 patients from collaborative sites were compared with those obtained from 54 treated patients and 56 patients taking placebo from a randomized controlled trial. Spinal fracture data were analyzed separately in mild to moderate bone loss of lumbar spine (baseline L2-L4 bone density [BD] > or = 65% young normal) and in severe bone loss (BD < 65%). Since demographic and fracture data were similar among fluoride-treated patients from the three trials at each stratum of bone loss, their data were combined. In mild to moderate bone loss, SR-NaF treatment in the combined group virtually eliminated new spinal fractures with 96.6% of patients remaining fracture-free. The Fluoride group had a markedly lower individual vertebral fracture rate (0.025 vs. 0.188/patient year, p = 0.0001) and group vertebral fracture rate (0.029 vs. 0.175/patient year, relative risk [RR] 0.12, p = 0.0001) than the Placebo group. In severe bone loss, the combined treated group had a significantly lower new spinal fracture rate than the Placebo group, although the differences were not as marked (group vertebral fracture rate of 0.150 vs. 0.276/patient year, RR 0.54, p = 0.03). In the combined fluoride-treated group, the L2-L4 bone mass rose by 4-6%/year for 4 years, and the femoral neck BD increased by 1-2%/year during first 2 years. The radial shaft BD did not change. The Placebo group did not show a change in bone mass at any site. The prevalence (percentage) of patients with related gastrointestinal side effects and nonvertebral fracture rates did not differ significantly between the combined SR-NaF group and the Placebo group (hip fracture rate of 0.0045/patient year in SR-NaF and 0.0053/patient year in Placebo; appendicular fracture other than hip (see text) rate of 0.0193/patient year in SR-NaF and 0.0159/patient year in Placebo). A subgroup analysis showed a low baseline L2-L4 BD, high prevalent spinal fractures, and reduced body weight to be important determinants of the development of spinal fracture during SR-NaF treatment. Concomitant medications (estrogen, vitamin D, thiazide and thyroid hormone) were not independent predictors of the spinal fracture risk. Only 17% of fluoride-treated patients were nonresponders (new spinal fractures or a fall/no change in L2-L4 bone mass). Thus, the effects of SR-NaF treatment on the spinal fracture rate from nonrandomized trials were similar to those of the treated group of the randomized trial but different from those of the Placebo group. The similarity of response of nonrandomized trials with that of the randomized controlled trial and the resultant combined analysis further validate the efficacy and safety of SR-NaF in the treatment of postmenopausal osteoporosis.

Bone Density↗
PubMed1996

Differentiation of the bone-tissue remodeling response to axial and torsional loading in the turkey ulna.

The ability of bone tissue to differentiate between axial and torsional loading was determined with use of a functionally isolated turkey-ulna model of bone adaptation. Surface modeling and intracortical remodeling were quantified after four weeks of 5000 cycles per day of axial loading sufficient to cause 1000 microstrain normal to the long axis of the bone (five ulnae), 5000 cycles per day of torsional loading sufficient to cause 1000 microstrain of shear strain (five ulnae), or disuse (six ulnae). Of these three distinct regimens, only disuse caused a significant change in gross areal properties (12 per cent loss of bone; p < 0.05) as compared with those in the contralateral, intact control ulnae (sixteen ulnae). This finding suggested that both axial and torsional loading conditions were suitable substitutes for functional signals normally responsible for bone homeostasis. However, the intracortical response was strongly dependent on the manner in which the bone was loaded. Axial loading increased the number of intracortical pores by a factor of seven as compared with that in the controls (246 +/- 40.5 compared with 36 +/- 8.5 pores); it also increased the area lost because of porosis as compared with that in the controls (1.39 +/- 0.252 compared with 0.202 +/- 0.062 square millimeter); however, the mean size of the individual pores was similar to that in the controls (0.00565 +/- 0.0019 compared with 0.00561 +/- 0.0029 square millimeter). Conversely, torsional loading failed to increase substantially the number of pores (67 +/- 22.6 pores), the area of bone lost because of porosis (0.352 +/- 0.114 square millimeter), or the size of the pores (0.00525 +/- 0.0035 square millimeter) as compared with those in the controls. Although disuse failed to increase substantially the number of intracortical pores (59 +/- 22.4 pores), significant area (1.05 +/- 0.35 square millimeters; p < 0.05) was lost within the cortex because of a threefold increase in the mean size of each pore (0.0178 +/- 0.0126 square millimeter). It appears that bone tissue can readily differentiate between distinct components of the strain environment, with strain per se necessary to retain coupled formation and resorption, shear strain achieving this goal by maintaining the status quo, and axial strain increasing intracortical turnover but retaining coupling. While it is clear that load influences bone mass and morphology, it is also clear that specific parameters within the strain environment have distinct strategic roles in defining this architecture.

Adaptation, Physiological↗
PubMed1995

Cystic carcinoma of the breast: a trap for the unwary.

Cystic breast masses are a common presentation to breast clinics. While the majority of cysts can be managed by simple aspiration, a small proportion are malignant. Histology records for a 10-year period have been examined to identify patients with cystic breast carcinomas. In all, 31 patients were identified. Of these, 18 had cystic degeneration of high-grade tumours, while 13 had intracystic papillary carcinoma. Both of these tumour types were diagnosed by a combination of cyst fluid cytology and breast imaging. The prognosis of high-grade tumours was poor, while that of intracystic papillary carcinomas was excellent. After cyst aspiration, bloodstained fluid should be sent for cytology and breast imaging arranged in all patients. Patients in whom a cyst refills within 2 week of aspiration require a careful re-evaluation. Cysts in postmenopausal women should be viewed with suspicion. Excision should be performed in patients with positive cytology or imaging.

Adult↗
PubMed1995

Management of fibroadenoma of the breast.

Fibroadenoma is a common cause of discrete breast lumps in young women. There is agreement that fibroadenomas can be diagnosed preoperatively with a high degree of confidence and that some of the lesions thus diagnosed will resolve, possibly obviating the need for excision. There is, however, wide disagreement over the proportion of fibroadenomas that resolve spontaneously and therefore the benefit that accrues from an expectant policy. The aim of this study was to audit the management of fibroadenomas on one unit and clarify their natural history over a 5-year period. A cohort of 70 women with 87 fibroadenomas diagnosed using a triple assessment of clinical examination, cytology and imaging (sonomammography) have been followed for a minimum of 5 years. In all, 53 of the 'fibroadenomas' have been excised. In four cases the histology revealed benign disease other than fibroadenoma; there were no neoplasms. The sensitivity of cytology and sonomammography for the diagnosis of fibroadenoma were 84% and 98% respectively. Thirty-four fibroadenomas have not been excised. Of 25 fibroadenomas that have been reassessed after at least 5 years of follow-up, 13 (52%) have reduced in size, 4 (16%) are unchanged in size and 8 (32%) have grown. No patient has developed a carcinoma at the site of the presumed fibroadenoma. This study confirms that an expectant management policy of fibroadenomas has not resulted in misdiagnosis of carcinomas. Further, since a significant proportion of fibroadenomas remain static or reduce in size over a 5-year period many women can avoid excision.

Adolescent↗
PubMed1994

The impact of the first 3 years of breast cancer screening on the overall presentation of breast cancer.

We have assessed the effect of the first round of the Breast Cancer Screening Programme on the presentation of breast cancer in the Southampton Health District with respect to number of cases and pathological characteristics. A retrospective comparative survey of the presentation of breast cancer in the 3 years prior to breast cancer screening (1985-1988) with the presentation of breast cancer during the prevalent round of breast cancer screening (1988-1991) was performed. During the period of study 1536 cases of breast cancer presented. Six hundred and sixty presented in the years prior to screening and 864 during the first round of screening. All patients lived within the Southampton Health District. The study was designed to assess the changes in breast cancer presentation with regard to age, pathological characteristics, and treatment. Even allowing for the increases in the local population there was a significant increase in the number of cases of breast cancer diagnosed (chi 2 = 23.7, df = 1, P < 0.001). The majority of this increase was in the 50-64 age group. There was also a significant shift towards an earlier stage at diagnosis and a significant reduction in tumour size when all cases were included (mean 26 mm versus 34 mm P < 0.001). Screening also created the opportunity for less invasive treatment. Consequently there was a rise in the number of excisions by localization biopsy from 1% to 13% during the screening period. In conclusion, the National Breast Cancer Screening Programme (NBCSP) has had a significant impact on the presentation of breast cancer.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Hearing loss and temporal bone structure in achondroplasia.

Characteristic temporal bone changes have recently been defined by high resolution CT in nine patients with achondroplasia (Cobb et al., Am J Neuroradiol 9:1195, 1988). These included narrowing of the skull base and "towering" petrous ridges resulting in abnormal orientation of the inner and middle ear structures. In order to determine whether these morphologic changes are the cause of the hearing deficit in achondroplasia, audiometric studies and ENT evaluation were performed in eight of the nine patients. All had a history of frequent otitis media and four had experienced tympanic membrane tube insertion. Three patients had significant sensorineural hearing loss, two had conductive hearing loss and one patient had combined hearing loss. None of the temporal bone morphologic changes were found to be correlated with the degree of either sensorineural or conductive hearing loss. Fusion of the ossicular chain was not present in any of our cases. Appropriate treatment of frequent acute otitis media and early awareness of middle ear effusions and conductive hearing loss in children with achondroplasia may be of great importance in preventing permanent hearing loss.

Achondroplasia↗
PubMed1993

Measurement of intrinsic bone quality in vivo by reflection ultrasound: correction of impaired quality with slow-release sodium fluoride and calcium citrate.

The intrinsic (material) quality of cancellous and cortical bone was evaluated in vivo from the measurement of reflection ultrasound velocities in the ulna. In cancellous bone, the reflection ultrasound velocity was inversely correlated with age in normal women (r = -0.48, p = 0.001), with a significantly lower mean value in 32 normal postmenopausal women than in 14 premenopausal women (3124 versus 3341 m/s, p < 0.0001). In 32 untreated osteoporotic women the cancellous bone velocity was lower than in normal postmenopausal subjects (2906 versus 3124 m/s, p = 0.0001). Following treatment with slow-release sodium fluoride plus calcium citrate (mean 2.4 years in 33 osteoporotic patients with no fracture during treatment), the cancellous bone velocity was significantly higher than in untreated osteoporotic women (3082 versus 2906 m/s, p = 0.0002) and was not significantly different from that in normal postmenopausal women. The cortical bone velocity displayed similar trends, but the changes did not attain statistical significance. The measurements were repeated approximately 9 months later in 9 untreated and in 20 treated patients; in 5 additional patients, the measurements were made both before and after 9 months of treatment with slow-release sodium fluoride and calcium citrate. The cancellous bone velocity increased significantly (p = 0.046) in these patients, from 3008 m/s before treatment to 3112 m/s after the first 9 months of treatment. The velocity rose significantly from 3037 to 3167 m/s (p = 0.017) in patients treated for a short time (12-30 months at first measurement), but it did not change in untreated patients or those treated for more than 30 months. Thus, the material quality of cancellous bone decreases with normal aging and is reduced further with the osteoporotic process. This impaired quality may be corrected by treatment with slow-release sodium fluoride plus calcium citrate.

Analysis of Variance↗
PubMed1993

Transcervical CVS sample size: correlation with placental location, cytogenetic findings, and pregnancy outcome.

Data from 2907 transcervical CVS cases performed on singleton pregnancies were reviewed retrospectively and villus sample size was correlated with cytogenetic results, placental location, maternal age at the expected date of confinement (EDC), gestational age at the time of sampling, birth weight, gestational age at the time of delivery, and pregnancy outcome. No correlation was noted between villus sample size and maternal age, gestational age at sampling, gestational age at delivery, birth weight, or pregnancy outcome. An inverse correlation between villus sample size and percentage of abnormal cytogenetic findings was statistically significant (chi 2 = 8.53, p < 0.01). The percentage of small samples was greater when the placenta was anterior, lateral, or fundal than when the placenta was posterior.

Adult↗